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Programmable logic controllerA programmable logic controller(PLC)or programmable controller is a digital computer used for automation of electromechanical processes,such as control of machinery on factory assembly lines,amusement rides,or lighting fixtures.PLCs are used in many industries and machines.Unlike general-purpose computers,the PLC is designed for multiple inputs and output arrangements,extended temperature ranges, immunity to electrical noise,and resistance to vibration and impact.Programs to control machine operation are typically stored in battery-backed or non-volatile memory.A PLC is an example of a real time system since output results must be produced in response to input conditions within a bounded time,otherwise unintended operation will result.1.HistoryThe PLC was invented in response to the needs of the American automotive manufacturing industry.Programmable logic controllers were initially adopted by the automotive industry where software revision replaced the re-wiring of hard-wired control panels when production models changed.Before the PLC,control,sequencing,and safety interlock logic for manufacturing automobiles was accomplished using hundreds or thousands of relays,cam timers, and drum sequencers and dedicated closed-loop controllers.The process for updating such facilities for the yearly model change-over was very time consuming and expensive,as electricians needed to individually rewire each and every relay.In1968GM Hydramatic(the automatic transmission division of General Motors) issued a request for proposal for an electronic replacement for hard-wired relay systems.The winning proposal came from Bedford Associates of Bedford, Massachusetts.The first PLC,designated the084because it was Bedford Associates' eighty-fourth project,was the result.Bedford Associates started a new company dedicated to developing,manufacturing,selling,and servicing this new product: Modicon,which stood for MOdular DIgital CONtroller.One of the people who worked on that project was Dick Morley,who is considered to be the"father"of the PLC.The Modicon brand was sold in1977to Gould Electronics,and later acquired by German Company AEG and then by French Schneider Electric,the current owner. One of the very first084models built is now on display at Modicon's headquarters in North Andover,Massachusetts.It was presented to Modicon by GM,when the unit was retired after nearly twenty years of uninterrupted service.Modicon used the84moniker at the end of its product range until the984made its appearance.The automotive industry is still one of the largest users of PLCs.2.DevelopmentEarly PLCs were designed to replace relay logic systems.These PLCs were programmed in"ladder logic",which strongly resembles a schematic diagram of relay logic.This program notation was chosen to reduce training demands for the existing technicians.Other early PLCs used a form of instruction list programming,based on a stack-based logic solver.Modern PLCs can be programmed in a variety of ways,from ladder logic to more traditional programming languages such as BASIC and C.Another method is State Logic,a very high-level programming language designed to program PLCs based on state transition diagrams.Many early PLCs did not have accompanying programming terminals that were capable of graphical representation of the logic,and so the logic was instead represented as a series of logic expressions in some version of Boolean format,similar to Boolean algebra.As programming terminals evolved,it became more common for ladder logic to be used,for the aforementioned reasons.Newer formats such as State Logic and Function Block(which is similar to the way logic is depicted when using digital integrated logic circuits)exist,but they are still not as popular as ladder logic.A primary reason for this is that PLCs solve the logic in a predictable and repeating sequence,and ladder logic allows the programmer(the person writing the logic)to see any issues with the timing of the logic sequence more easily than would be possible in other formats.2.1ProgrammingEarly PLCs,up to the mid-1980s,were programmed using proprietary programming panels or special-purpose programming terminals,which often had dedicated function keys representing the various logical elements of PLC programs. Programs were stored on cassette tape cartridges.Facilities for printing and documentation were very minimal due to lack of memory capacity.The very oldest PLCs used non-volatile magnetic core memory.More recently,PLCs are programmed using application software on personal computers.The computer is connected to the PLC through Ethernet,RS-232,RS-485 or RS-422cabling.The programming software allows entry and editing of the ladder-style logic.Generally the software provides functions for debugging andtroubleshooting the PLC software,for example,by highlighting portions of the logic to show current status during operation or via simulation.The software will upload and download the PLC program,for backup and restoration purposes.In some models of programmable controller,the program is transferred from a personal computer to the PLC though a programming board which writes the program into a removable chip such as an EEPROM or EPROM.3.FunctionalityThe functionality of the PLC has evolved over the years to include sequential relay control,motion control,process control,distributed control systems and networking. The data handling,storage,processing power and communication capabilities of some modern PLCs are approximately equivalent to desktop computers.PLC-like programming combined with remote I/O hardware,allow a general-purpose desktop computer to overlap some PLCs in certain applications.Regarding the practicality of these desktop computer based logic controllers,it is important to note that they have not been generally accepted in heavy industry because the desktop computers run on less stable operating systems than do PLCs,and because the desktop computer hardware is typically not designed to the same levels of tolerance to temperature, humidity,vibration,and longevity as the processors used in PLCs.In addition to the hardware limitations of desktop based logic,operating systems such as Windows do not lend themselves to deterministic logic execution,with the result that the logic may not always respond to changes in logic state or input status with the extreme consistency in timing as is expected from PLCs.Still,such desktop logic applications find use in less critical situations,such as laboratory automation and use in small facilities where the application is less demanding and critical,because they are generally much less expensive than PLCs.In more recent years,small products called PLRs(programmable logic relays),and also by similar names,have become more common and accepted.These are very much like PLCs,and are used in light industry where only a few points of I/O(i.e.a few signals coming in from the real world and a few going out)are involved,and low cost is desired.These small devices are typically made in a common physical size and shape by several manufacturers,and branded by the makers of larger PLCs to fill out their low end product range.Popular names include PICO Controller,NANO PLC, and other names implying very small controllers.Most of these have between8and 12digital inputs,4and8digital outputs,and up to2analog inputs.Size is usuallyabout4"wide,3"high,and3"deep.Most such devices include a tiny postage stamp sized LCD screen for viewing simplified ladder logic(only a very small portion of the program being visible at a given time)and status of I/O points,and typically these screens are accompanied by a4-way rocker push-button plus four more separate push-buttons,similar to the key buttons on a VCR remote control,and used to navigate and edit the logic.Most have a small plug for connecting via RS-232or RS-485to a personal computer so that programmers can use simple Windows applications for programming instead of being forced to use the tiny LCD and push-button set for this purpose.Unlike regular PLCs that are usually modular and greatly expandable,the PLRs are usually not modular or expandable,but their price can be two orders of magnitude less than a PLC and they still offer robust design and deterministic execution of the logic.4.PLC Topics4.1.FeaturesThe main difference from other computers is that PLCs are armored for severe conditions(such as dust,moisture,heat,cold)and have the facility for extensive input/output(I/O)arrangements.These connect the PLC to sensors and actuators. PLCs read limit switches,analog process variables(such as temperature and pressure), and the positions of complex positioning systems.Some use machine vision.On the actuator side,PLCs operate electric motors,pneumatic or hydraulic cylinders, magnetic relays,solenoids,or analog outputs.The input/output arrangements may be built into a simple PLC,or the PLC may have external I/O modules attached to a computer network that plugs into the PLC.4.2System scaleA small PLC will have a fixed number of connections built in for inputs and outputs. Typically,expansions are available if the base model has insufficient I/O.Modular PLCs have a chassis(also called a rack)into which are placed modules with different functions.The processor and selection of I/O modules is customised for the particular application.Several racks can be administered by a single processor,and may have thousands of inputs and outputs.A special high speed serial I/O link is used so that racks can be distributed away from the processor,reducing the wiring costs for large plants.4.3User interfacePLCs may need to interact with people for the purpose of configuration,alarmreporting or everyday control.A simple system may use buttons and lights to interact with the user.Text displays are available as well as graphical touch screens.More complex systems use a programming and monitoring software installed on a computer,with the PLC connected via a communication interface.4.4CommunicationsPLCs have built in communications ports,usually9-pin RS-232,but optionally EIA-485or Ethernet.Modbus,BACnet or DF1is usually included as one of the communications protocols.Other options include various fieldbuses such as DeviceNet or Profibus.Other communications protocols that may be used are listed in the List of automation protocols.Most modern PLCs can communicate over a network to some other system,such as a computer running a SCADA(Supervisory Control And Data Acquisition)system or web browser.PLCs used in larger I/O systems may have peer-to-peer(P2P)communication between processors.This allows separate parts of a complex process to have individual control while allowing the subsystems to co-ordinate over the communication link.These communication links are also often used for HMI devices such as keypads or PC-type workstations.4.5ProgrammingPLC programs are typically written in a special application on a personal computer, then downloaded by a direct-connection cable or over a network to the PLC.The program is stored in the PLC either in battery-backed-up RAM or some other non-volatile flash memory.Often,a single PLC can be programmed to replace thousands of relays.Under the IEC61131-3standard,PLCs can be programmed using standards-based programming languages.A graphical programming notation called Sequential Function Charts is available on certain programmable controllers.Initially most PLCs utilized Ladder Logic Diagram Programming,a model which emulated electromechanical control panel devices(such as the contact and coils of relays) which PLCs replaced.This model remains common today.IEC61131-3currently defines five programming languages for programmable control systems:FBD(Function block diagram),LD(Ladder diagram),ST (Structured text,similar to the Pascal programming language),IL(Instruction list,similar to assembly language)and SFC(Sequential function chart).These techniques emphasize logical organization of operations.While the fundamental concepts of PLC programming are common to all manufacturers,differences in I/O addressing,memory organization and instruction sets mean that PLC programs are never perfectly interchangeable between different makers.Even within the same product line of a single manufacturer,different models may not be directly compatible.5.PLC compared with other control systemsPLCs are well-adapted to a range of automation tasks.These are typically industrial processes in manufacturing where the cost of developing and maintaining the automation system is high relative to the total cost of the automation,and where changes to the system would be expected during its operational life.PLCs contain input and output devices compatible with industrial pilot devices and controls;little electrical design is required,and the design problem centers on expressing the desired sequence of operations.PLC applications are typically highly customized systems so the cost of a packaged PLC is low compared to the cost of a specific custom-built controller design.On the other hand,in the case of mass-produced goods,customized control systems are economic due to the lower cost of the components,which can be optimally chosen instead of a"generic"solution,and where the non-recurring engineering charges are spread over thousands or millions of units.For high volume or very simple fixed automation tasks,different techniques are used.For example,a consumer dishwasher would be controlled by an electromechanical cam timer costing only a few dollars in production quantities.A microcontroller-based design would be appropriate where hundreds or thousands of units will be produced and so the development cost(design of power supplies, input/output hardware and necessary testing and certification)can be spread over many sales,and where the end-user would not need to alter the control.Automotive applications are an example;millions of units are built each year,and very few end-users alter the programming of these controllers.However,some specialty vehicles such as transit busses economically use PLCs instead of custom-designed controls, because the volumes are low and the development cost would be uneconomic.Very complex process control,such as used in the chemical industry,may require algorithms and performance beyond the capability of even high-performance PLCs. Very high-speed or precision controls may also require customized solutions;forexample,aircraft flight controls.Programmable controllers are widely used in motion control,positioning control and torque control.Some manufacturers produce motion control units to be integrated with PLC so that G-code(involving a CNC machine)can be used to instruct machine movements.PLCs may include logic for single-variable feedback analog control loop,a "proportional,integral,derivative"or"PID controller".A PID loop could be used to control the temperature of a manufacturing process,for example.Historically PLCs were usually configured with only a few analog control loops;where processes required hundreds or thousands of loops,a distributed control system(DCS)would instead be used.As PLCs have become more powerful,the boundary between DCS and PLC applications has become less distinct.PLCs have similar functionality as Remote Terminal Units.An RTU,however, usually does not support control algorithms or control loops.As hardware rapidly becomes more powerful and cheaper,RTUs,PLCs and DCSs are increasingly beginning to overlap in responsibilities,and many vendors sell RTUs with PLC-like features and vice versa.The industry has standardized on the IEC61131-3functional block language for creating programs to run on RTUs and PLCs,although nearly all vendors also offer proprietary alternatives and associated development environments.6.Digital and analog signalsDigital or discrete signals behave as binary switches,yielding simply an On or Off signal(1or0,True or False,respectively).Push buttons,limit switches,and photoelectric sensors are examples of devices providing a discrete signal.Discrete signals are sent using either voltage or current,where a specific range is designated as On and another as Off.For example,a PLC might use24V DC I/O,with values above22V DC representing On,values below2VDC representing Off,and intermediate values undefined.Initially,PLCs had only discrete I/O.Analog signals are like volume controls,with a range of values between zero and full-scale.These are typically interpreted as integer values(counts)by the PLC,with various ranges of accuracy depending on the device and the number of bits available to store the data.As PLCs typically use16-bit signed binary processors,the integer values are limited between-32,768and+32,767.Pressure,temperature,flow,and weight are often represented by analog signals.Analog signals can use voltage or current with a magnitude proportional to the value of the process signal.For example,an analog0-10V input or4-20mA would be converted into an integer value of0-32767.可编程序逻辑控制器可编程序逻辑控制器(PLC)或可编程控制器是一种数字计算机用于机电自动化流程,控制机械工厂生产线等游乐项目,或照明灯具。

电气工程及其自动化专业_外文文献_英文文献_外文翻译_plc方面.

1、外文原文A: Fundamentals of Single-chip MicrocomputerTh e si ng le -c hi p m ic ro co mp ut er i s t he c ul mi na ti on of both t h e de ve lo pm en t of the dig it al com pu te r an d th e in te gr at ed c i rc ui t arg ua bl y t h e tow m os t s ig ni f ic an t i nv en ti on s o f t he 20th c e nt ur y [1].Th es e tow type s of arch it ec tu re are foun d in sin g le -ch i p m i cr oc om pu te r. Som e empl oy the spli t prog ra m/da ta me mo ry of the H a rv ar d ar ch it ect u re , sh ow n in Fig.3-5A -1, oth ers fo ll ow the p h il os op hy , wi del y ada pt ed for gen er al -p ur po se com pu te rs and m i cr op ro ce ss o r s, o f ma ki ng no log i ca l di st in ct ion be tw ee n p r og ra m and dat a me mo ry as in the Pr in ce to n arch ite c tu re , show n i n Fig.3-5A-2.In gen er al ter ms a sin gl e -chi p mic ro co mp ut er i sc h ar ac te ri zed b y t he i nc or po ra ti on of a ll t he un it s of a co mp uter i n to a sin gl e d ev i ce , as sho wn inFi g3-5A -3.Fig.3-5A-1 A Harvard typeFig.3-5A-2. A conventional Princeton computerFig3-5A-3. Principal features of a microcomputerRead only memory (ROM.R OM is usua ll y for the pe rm an ent,n o n-vo la ti le stor a ge of an app lic a ti on s pr og ra m .M an ym i cr oc om pu te rs and m are inte nd e d for high -v ol um e ap pl ic at ions a n d he nc e t h e eco n om ic al man uf act u re of th e de vic e s re qu ir es t h at t he cont en t s o f t he prog ra m me m or y be co mm it t ed perm a ne ntly d u ri ng the man ufa c tu re of ch ip s .Cl ea rl y, thi s im pl ie s a r i go ro us app ro ach to ROM cod e deve l op me nt sin ce cha ng es can not b e mad e afte r manu f a c tu re .Th is dev e lo pm en t proc ess may invo lv e e m ul at io n us in g aso ph is ti ca te d de ve lo pm en t sy ste m wit h a h a rd wa re emu la tio n cap ab il it y as w el l as the use o f po we rf ul s o ft wa re too ls.So me man uf act u re rs pro vi de add it io na l RO M opt i on s by i n cl ud in g in their ra n ge dev ic es wit h (or int en de d fo r use wit h u s er pro gr am ma ble me mo ry. Th e sim p le st of th es e is usu al ly d e vi ce whi ch can op er at e in a micro p ro ce ssor mod e by usi ng som e o f the inp ut /outp u t li ne s as an ad dr es s an d da ta b us fora c ce ss in g ex te rna l mem or y. Thi s t y pe of de vi ce can beh av ef u nc ti on al ly as th e sing le chip mi cr oc om pu te r from whi ch it is d e ri ve d al be it wit h re st ri ct ed I/O and a mod if ied ex te rn al c i rc ui t. The use of thes e d ev ic es is com mo n eve n in prod uc ti on c i rc ui ts wher e t he vo lu me does no tj us ti f y t h e d ev el o pm en t c osts o f c us to m o n -ch i p R OM [2];t he re c a n s ti ll bea s ignif i ca nt saving i n I /O and o th er c h ip s com pa re d to a conv en ti on al mi c ro pr oc es sor b a se d ci rc ui t. Mor e ex ac t re pl ace m en t fo r RO M dev i ce s ca n be o b ta in ed in th e fo rm of va ri an ts w it h 'p ig gy -b ack 'E P RO M(Er as ab le pro gr am ma bl e ROM s oc ke ts or dev ic e s with EPROM i n st ea d o f RO M 。

关于PLC的外文及翻译

PLCs --Past, Present and FutureEveryone knows there's only one constant in the technology world, and that's change. This is especially evident in the evolution of Programmable Logic Controllers (PLC) and their varied applications. From their introduction more than 30 years ago, PLCs have become the cornerstone of hundreds of thousands of control systems in a wide range of industries.At heart, the PLC is an industrialized computer programmed with highly specialized languages, and it continues to benefit from technological advances in the computer and information technology worlds. The most prominent of which is miniaturization and communications.The Shrinking PLCWhen the PLC was first introduced, its size was a major improvement - relative to the hundreds of hard-wired relays and timers it replaced. A typical unit housing a CPU and I/O was roughly the size of a 19 television set. Through the 1980s and early 1990s, modular PLCs continued to shrink in footprint while increasing in capabilities and performance (see Diagram 1 for typical modular PLC configuration).In recent years, smaller PLCs have been introduced in the nano and micro classes that offer features previously found only in larger PLCs. This has made specifying a larger PLC just for additional features or performance, and not increased I/O count, unnecessary, as even those in the nano class are capable of Ethernet communication, motion control, on-board PID with autotune, remote connectivity and more.PLCs are also now well-equipped to replace stand-alone process controllers in many applications, due to their ability to perform functions of motion control, data acquisition, RTU (remote telemetry unit) and even some integrated HMI (human machine interface) functions. Previously, these functions often required their own purpose-built controllers and software, plus a separate PLC for the discrete control and interlocking.The Great CommunicatorPossibly the most significant change in recent years lies in the communications arena. In the 1970s Modicon introduction of Modbus communications protocol allowed PLCs to communicate over standard cabling. This translates to an ability to place PLCs in closer proximity to real world devices and communicate back to other system controls in a main panel.In the past 30 years we have seen literally hundreds of proprietary and standard protocols developed, each with their own unique advantages.Today's PLCs have to bedata compilers and information gateways. They have to interface with bar code scanners and printers, as well as temperature and analog sensors. They need multiple protocol support to be able to connect with other devices in the process. And furthermore, they need all these capabilities while remaining cost-effective and simple to program.Another primary development that has literally revolutionized the way PLCs are programmed, communicate with each other and interface with PCs for HMI, SCADA or DCS applications, came from the computing world.Use of Ethernet communications on the plant floor has doubled in the past five years. While serial communications remain popular and reliable, Ethernet is fast becoming the communications media of choice with advantages that simply can't be ignored, such as: Network speed. Ease of use when it comes to the setup and wiring. Availability of off-the-shelf networking components. Built-in communications setups.Integrated Motion ControlAnother responsibility the PLC has been tasked with is motion control. From simple open-loop to multi-axis applications, the trend has been to integrate this feature into PLC hardware and software.There are many applications that require accurate control at a fast pace, but not exact precision at blazing speeds. These are applications where the stand-alone PLC works well. Many nano and micro PLCs are available with high-speed counting capabilities and high-frequency pulse outputs built into the controller, making them a viable solution for open-loop control.The one caveat is that the controller does not know the position of the output device during the control sequence. On the other hand, its main advantage is cost. Even simple motion control had previously required an expensive option module, and at times was restricted to more sophisticated control platforms in order to meet system requirements.More sophisticated motion applications require higher-precision positioning hardware and software, and many PLCs offer high-speed option modules that interface with servo drives. Most drives today can accept traditional commands from host (PLC or PC) controls, or provide their own internal motion control. The trend here is to integrate the motion control configuration into the logic controller programming software package.Programming LanguagesA facet of the PLC that reflects both the past and the future is programming language. The IEC 61131-3 standard deals with programming languages and defines two graphical and two textual PLC programming language standards: Ladder logic (graphical). Function block diagram (graphical). Structured text (textual).Instruction list (textual).This standard also defines graphical and textual sequential function chart elements to organize programs for sequential and parallel control processing. Based on the standard, many manufacturers offer at least two of these languages as options for programming their PLCs. Ironically, approximately 96 percent of PLC users recently still use ladder diagrams to construct their PLC code. It seems that ladder logic continues to be a top choice given it's performed so well for so long.Hardware PlatformsThe modern PLC has incorporated many types of Commercial off the Shelf (COTS) technology in its CPU. This latest technology gives the PLC a faster, more powerful processor with more memory at less cost. These advances have also allowed the PLC to expand its portfolio and take on new tasks like communications, data manipulation and high-speed motion without giving up the rugged and reliable performance expected from industrial control equipment.New technology has also created a category of controllers called Programmable Automation Controllers, or PACs. PACs differ from traditional PLCs in that they typically utilize open, modular architectures for both hardware and software, using de facto standards for network interfaces, languages and protocols. They could be viewed as a PC in an industrial PLC-like package.The FutureA 2005 PLC Product Focus Study from Reed Research Group pointed out factors increasingly important to users, machine builders and those making the purchasing decisions. The top picks for features of importance were.The ability to network, and do so easily. Ethernet communications is leading the charge in this realm. Not only are new protocols surfacing, but many of the industry de facto standard serial protocols that have been used for many years are being ported to Ethernet platforms. These include Modbus (ModbusTCP), DeviceNet (Ethernet/IP) and Profibus (Profinet). Ethernet communication modules for PLCs are readily available with high-speed performance and flexible protocols. Also, many PLC CPUs are now available with Ethernet ports on board, saving I/O slot space. PLCs will continue to develop more sophisticated connectivity to report information to other PLCs, system control systems, data acquisition (SCADA) systems and enterprise resource planning (ERP) systems. Additionally, wireless communications will continue to gain popularity.The ability to network PLC I/O connections with a PC. The same trends that have benefited PLC networking have migrated to the I/O level. Many PLC manufacturers are supporting the most accepted fieldbus networks, allowing PLC I/O to be distributed over large physical distances, or located where it was previously considered nearly impossible. This has opened the door for personal computers to interface with standard PLC I/O subsystems by using interface cards, typically supplied by the PLC manufacturer or a third party developer. Now these challenging locations can be monitored with today a PC. Where industrial-grade control engines are not required, the user can take advantage of more advanced software packages and hardware flexibility at a lower cost.The ability to use universal programming software for multiple targets/platforms. In the past it was expected that an intelligent controller would be complex to program. That is no longer the case. Users are no longer just trained programmers, such as design engineers or systems integrators, but end-users who expect easier-to-use software in more familiar formats. The Windows-based look and feel that users are familiar with on their personal computers have become the most accepted graphical user interface. What began as simple relay logic emulation for programming PLCs has evolved into languages that use higher level function blocks that are much more intuitive to configure. PLC manufacturers are also beginning to integrate the programming of diverse functions that allow you to learn only one package in configuring logic, HMI, motion control and other specialized capabilities. Possibly the ultimate wish of the end-user would be for a software package that could seamlessly program many manufacturers PLCs and sub-systems. After all, Microsoft Windows operating system and applications work similarly whether installed on a Dell, HP or IBM computer, which makes it easier for the user.Overall, PLC users are satisfied with the products currently available, while keeping their eye on new trends and implementing them where the benefits are obvious. Typically, new installations take advantage of advancing technologies, helping them become more accepted in the industrial world.PLC的过去、现在与未来众所周知，科技世界里只有一个永恒真理，那就是变化。

可编程控制器外文翻译、中英文翻译、外文文献翻译

毕业设计中英文翻译院系专业班级姓名学号指导教师20**年 4 月Programmable Logic Controllers (PLC)1、MotivationProgrammable Logic Controllers (PLC), a computing device invented by Richard E. Morley in 1968, have been widely used in industry including manufacturing systems, transportation systems, chemical process facilities, and many others. At that time, the PLC replaced the hardwired logic with soft-wired logic or so-called relay ladder logic (RLL), a programming language visually resembling the hardwired logic, and reduced thereby the configuration time from 6 months down to 6 days [Moody and Morley, 1999].Although PC based control has started to come into place, PLC based control will remain the technique to which the majority of industrial applications will adhere due to its higher performance, lower price, and superior reliability in harsh environments. Moreover, according to a study on the PLC market of Frost and Sullivan [1995], an increase of the annual sales volume to 15 million PLCs per year with the hardware value of more than 8 billion US dollars has been predicted, though the prices of computing hardware is steadily dropping. The inventor of the PLC, Richard E Morley, fairly considers the PLC market as a 5-billion industry at the present time.Though PLCs are widely used in industrial practice, the programming of PLC based control systems is still very much relying on trial-and-error. Alike software engineering, PLC software design is facing the software dilemma or crisis in a similar way. Morley himself emphasized this aspect most forcefully by indicating [Moody and Morley, 1999, p. 110]:`If houses were built like software projects, a single woodpecker could destroy civilization.”Particularly, practical problems in PLC programming are to eliminate software bugs and to reduce the maintenance costs of old ladder logic programs. Though the hardware costs of PLCs are dropping continuously, reducing the scan time of the ladder logic is still an issue in industry so that low-cost PLCs can be used.In general, the productivity in generating PLC is far behind compared to other domains, for instance, VLSI design, where efficient computer aided design tools are in practice. Existent software engineering methodologies are not necessarily applicable to the PLC basedsoftware design because PLC-programming requires a simultaneous consideration of hardware and software. The software design becomes, thereby, more and more the major cost driver. In many industrial design projects, more than SO0/a of the manpower allocated for the control system design and installation is scheduled for testing and debugging PLC programs [Rockwell, 1999].In addition, current PLC based control systems are not properly designed to support the growing demand for flexibility and reconfigurability of manufacturing systems. A further problem, impelling the need for a systematic design methodology, is the increasing software complexity in large-scale projects.PLCs (programmable logic controllers) are the control hubs for a wide variety of automated systems and processes. They contain multiple inputs and outputs that use transistors and other circuitry to simulate switches and relays to control equipment. They are programmable via software interfaced via standard computer interfaces and proprietary languages and network options.Programmable logic controllers I/O channel specifications include total number of points, number of inputs and outputs, ability to expand, and maximum number of channels. Number of points is the sum of the inputs and the outputs. PLCs may be specified by any possible combination of these values. Expandable units may be stacked or linked together to increase total control capacity. Maximum number of channels refers to the maximum total number of input and output channels in an expanded system. PLC system specifications to consider include scan time, number of instructions, data memory, and program memory. Scan time is the time required by the PLC to check the states of its inputs and outputs. Instructions are standard operations (such as math functions) available to PLC software. Data memory is the capacity for data storage. Program memory is the capacity for control software.Available inputs for programmable logic controllers include DC, AC, analog, thermocouple, RTD, frequency or pulse, transistor, and interrupt inputs. Outputs for PLCs include DC, AC, relay, analog, frequency or pulse, transistor, and triac. Programming options for PLCs include front panel, hand held, and computer.Programmable logic controllers use a variety of software programming languages for control. These include IEC 61131-3, sequential function chart (SFC), function block diagram (FBD), ladder diagram (LD), structured text (ST), instruction list (IL), relay ladder logic (RLL), flow chart, C, and Basic. The IEC 61131-3 programming environment provides support for five languages specified by the global standard: Sequential Function Chart,Function Block Diagram, Ladder Diagram, Structured Text, and Instruction List. This allows for multi-vendor compatibility and multi-language programming. SFC is a graphical language that provides coordination of program sequences, supporting alternative sequence selections and parallel sequences. FBD uses a broad function library to build complex procedures in a graphical format. Standard math and logic functions may be coordinated with customizable communication and interface functions. LD is a graphic language for discrete control and interlocking logic. It is completely compatible with FBD for discrete function control. ST is a text language used for complex mathematical procedures and calculations less well suited to graphical languages. IL is a low-level language similar to assembly code. It is used in relatively simple logic instructions. Relay Ladder Logic (RLL), or ladder diagrams, is the primary programming language for programmable logic controllers (PLCs). Ladder logic programming is a graphical representation of the program designed to look like relay logic. Flow Chart is a graphical language that describes sequential operations in a controller sequence or application. It is used to build modular, reusable function libraries. C is a high level programming language suited to handle the most complex computation, sequential, and data logging tasks. It is typically developed and debugged on a PC. BASIC is a high level language used to handle mathematical, sequential, data capturing and interface functions.Programmable logic controllers can also be specified with a number of computer interface options, network specifications and features. PLC power options, mounting options and environmental operating conditions are all also important to consider.2、ResumeA PLC (programmable Logic Controller) is a device that was invented to replace the necessary sequential relay circuits for control.The PLC works by looking at its input and depending upon their state, turning on/off its outputs. The user enters a program, usually via software or programmer, which gives the desired results.PLC is used in many "real world" applications. If there is industry present, chance are good that there is a PLC present. If you are involved in machining, packing, material handling, automated assembly or countless other industries, you are probably already using them. If you are not, you are wasting money and time. Almost any application that needs some type of electrical control has a need for a PLC.For example, let's assume that when a switch turns on we want to turn a solenoid on for 5second and then turn it off regardless of how long the switch is on for. We can do this with a simple external timer. But what if the process included 10 switches and solenoids? We should need 10 external times. What if the process also needed to count how many times the switch individually turned on? We need a lot of external counters.As you can see the bigger the process the more of a need we have for a PLC. We can simply program the PLC to count its input and turn the solenoids on for the specified time.We will take a look at what is considered to be the "top 20" PLC instructions. It can be safely estimated that with a firm understanding of these instructions one can solve more than 80% of the applications in existence.Of course we will learn more than just these instruction to help you solve almost ALL potential PLC applications.The PLC mainly consists of a CPU, memory areas, and appropriate circuits to receive input/output data. We can actually consider the PLC to be a box full of hundreds or thousands of separate relay, counters, times and data storage locations,Do these counters,timers, etc. really exist? No,they don't "physically" exist but rather they simulated and be considered software counters, timers, etc. . These internal relays are simulated through bit locations in registers.What does each part do? Let me tell you.Input RelaysThese are connected to the outside world.They physically exsit and receive signals from switches,sensors,ect..Typically they are not relays but rather they are transistors.Internal Utility RelaysThese do not receive signals from the outside world nor do they physically exist.they are simulated relays and are what enables a PLC to eliminate external relays.There are also some special relays that are dedicated to performing only one task.Some are always on while some are always off.Some are on only once during power-on and are typically used for initializing data that was stored.CountersThese again do not physically exist. They are simulated counters and they can be programmed to count pulses.Typically these counters can count up,down or both up anddown.Since they are simulated,they are limited in their counting speed.Some manufacturers also include high-speed counters that are hardware based.We think of these as physically existing.Most times these counters can count up,down or up and down.TimersThese also do not physically exist.They come in many varieties and increments.The most common type is an on-delay type.Others include off-delays and both retentive and non-retentive types.Increments vary from 1ms through 1s.Output RelaysThere are connected to the outside world.They physically exist and send on/off signals to solenoids,lights,etc..They can be transistors,relays,or triacs depending upon the model chosen Data StorageTypically there are registers assigned to simply store data.They are usually used as temporary storage for math or data manipulation.They can also typically be used to store data when power is removed form the PLC.Upon power-up they will still have the same contents as before power was moved.Very convenient and necessary!A PLC works by continually scanning a program.We can think of this scan cycle as consisting of 3 important steps.There are typically more than 3 but we can focus on the important parts and not worry about the others,Typically the others are checking the system and updating the current internal counter and timer values,Step 1 is to check input status,First the PLC takes a look at each input to determine if it is on off.In other words,is the sensor connected to the first input on?How about the third...It records this data into its memory to be used during the next step.Step 2 is to execute program.Next the PLC executes your program one instruction at a time.Maybe your program said that if the first input was on then it should turn on the first output.Since it already knows which inputs are on/off from the previous step,it will be able to decide whether the first output should be turned on based on the state of the first input.It will store the execution results for use later during the next step.Step 3 is to update output status.Finally the PLC updates the status the outputs.It updates the outputs based on which inputs were on during the first step and the results executing your program during the second step.Based on the example in step 2 it would now turn on the firstoutput because the first input was on and your program said to turn on the first output when this condition is true.After the third step the PLC goes back to step one repeats the steps continuously.One scan time is defined as the time it takes to execute the 3 steps continuously.One scan time is defined as the time it takes to execute the 3 steps listed above.Thus a practical system is controlled to perform specified operations as desired.3、PLC StatusThe lack of keyboard, and other input-output devices is very noticeable on a PLC. On the front of the PLC there are normally limited status lights. Common lights indicate;power on - this will be on whenever the PLC has powerprogram running - this will often indicate if a program is running, or if no program is runningfault - this will indicate when the PLC has experienced a major hardware or software problemThese lights are normally used for debugging. Limited buttons will also be provided for PLC hardware. The most common will be a run/program switch that will be switched to program when maintenance is being conducted, and back to run when in production. This switch normally requires a key to keep unauthorized personnel from altering the PLC program or stopping execution. A PLC will almost never have an on-off switch or reset button on the front. This needs to be designed into the remainder of the system.The status of the PLC can be detected by ladder logic also. It is common for programs to check to see if they are being executed for the first time, as shown in Figure 1. The ’first scan’ input will be true on the very first time the ladder logic is scanned, but false on every other scan. In this case the address for ’first scan’ in a PLC-5 is ’S2:1/14’. With the logic in the example the first scan will seal on ’light’, until ’clear’ is turned on. So the light will turn on after the PLC has been turned on, but it will turn off and stay off after ’clear’ is turned on. The ’first scan’ bit is also referred to at the ’first pass’ bit.Figure 1 An program that checks for the first scan of the PLC4、Memory TypesThere are a few basic types of computer memory that are in use today.RAM (Random Access Memory) - this memory is fast, but it will lose its contents when power is lost, this is known as volatile memory. Every PLC uses this memory for the central CPU when running the PLC.ROM (Read Only Memory) - this memory is permanent and cannot be erased. It is often used for storing the operating system for the PLC.EPROM (Erasable Programmable Read Only Memory) - this is memory that can be programmed to behave like ROM, but it can be erased with ultraviolet light and reprogrammed.EEPROM (Electronically Erasable Programmable Read Only Memory) – This memory can store programs like ROM. It can be programmed and erased using a voltage, so it is becoming more popular than EPROMs.All PLCs use RAM for the CPU and ROM to store the basic operating system for the PLC. When the power is on the contents of the RAM will be kept, but the issue is what happens when power to the memory is lost. Originally PLC vendors used RAM with a battery so that the memory contents would not be lost if the power was lost. This method is still in use, but is losing favor. EPROMs have also been a popular choice for programming PLCs. The EPROM is programmed out of the PLC, and then placed in the PLC. When the PLC is turned on the ladder logic program on the EPROM is loaded into the PLC and run. This method can be very reliable, but the erasing and programming technique can be time consuming. EEPROM memories are a permanent part of the PLC, and programs can be stored in them like EPROM. Memory costs continue to drop, and newer types (such as flash memory) are becoming available, and these changes will continue to impact PLCs.5、Objective and Significance of the ThesisThe objective of this thesis is to develop a systematic software design methodology for PLC operated automation systems. The design methodology involves high-level description based on state transition models that treat automation control systems as discrete event systems, a stepwise design process, and set of design rules providing guidance and measurements to achieve a successful design. The tangible outcome of this research is to find a way to reduce the uncertainty in managing the control software development process, that is, reducing programming and debugging time and their variation, increasing flexibility of theautomation systems, and enabling software reusability through modularity. The goal is to overcome shortcomings of current programming strategies that are based on the experience of the individual software developer.A systematic approach to designing PLC software can overcome deficiencies in the traditional way of programming manufacturing control systems, and can have wide ramifications in several industrial applications. Automation control systems are modeled by formal languages or, equivalently, by state machines. Formal representations provide a high-level description of the behavior of the system to be controlled. State machines can be analytically evaluated as to whether or not they meet the desired goals. Secondly, a state machine description provides a structured representation to convey the logical requirements and constraints such as detailed safety rules. Thirdly, well-defined control systems design outcomes are conducive to automatic code generation- An ability to produce control software executable on commercial distinct logic controllers can reduce programming lead-time and labor cost. In particular, the thesis is relevant with respect to the following aspect Customer-Driven ManufacturingIn modern manufacturing, systems are characterized by product and process innovation, become customer-driven and thus have to respond quickly to changing system requirements.A major challenge is therefore to provide enabling technologies that can economically reconfigure automation control systems in response to changing needs and new opportunities. Design and operational knowledge can be reused in real-time, therefore, giving a significant competitive edge in industrial practice.Higher Degree of Design Automation and Software QualityStudies have shown that programming methodologies in automation systems have not been able to match rapid increase in use of computing resources. For instance, the programming of PLCs still relies on a conventional programming style with ladder logic diagrams. As a result, the delays and resources in programming are a major stumbling stone for the progress of manufacturing industry. Testing and debugging may consume over 50% of the manpower allocated for the PLC program design. Standards [IEC 60848, 1999; IEC-61131-3, 1993; IEC 61499, 1998; ISO 15745-1, 1999] have been formed to fix and disseminate state-of-the-art design methods, but they normally cannot participate in advancingthe knowledge of efficient program and system design.A systematic approach will increase the level of design automation through reusing existing software components, and will provide methods to make large-scale system design manageable. Likewise, it will improve software quality and reliability and will be relevant to systems high security standards, especially those having hazardous impact on the environment such as airport control, and public railroads.System ComplexityThe software industry is regarded as a performance destructor and complexity generator. Steadily shrinking hardware prices spoils the need for software performance in terms of code optimization and efficiency. The result is that massive and less efficient software code on one hand outpaces the gains in hardware performance on the other hand. Secondly, software proliferates into complexity of unmanageable dimensions; software redesign and maintenance-essential in modern automation systems-becomes nearly impossible. Particularly, PLC programs have evolved from a couple lines of code 25 years ago to thousands of lines of code with a similar number of 1/O points. Increased safety, for instance new policies on fire protection, and the flexibility of modern automation systems add complexity to the program design process. Consequently, the life-cycle cost of software is a permanently growing fraction of the total cost. 80-90% of these costs are going into software maintenance, debugging, adaptation and expansion to meet changing needs [Simmons et al., 1998].Design Theory DevelopmentToday, the primary focus of most design research is based on mechanical or electrical products. One of the by-products of this proposed research is to enhance our fundamental understanding of design theory and methodology by extending it to the field of engineering systems design. A system design theory for large-scale and complex system is not yet fully developed. Particularly, the question of how to simplify a complicated or complex design task has not been tackled in a scientific way. Furthermore, building a bridge between design theory and the latest epistemological outcomes of formal representations in computer sciences and operations research, such as discrete event system modeling, can advance future development in engineering design.Application in Logical Hardware DesignFrom a logical perspective, PLC software design is similar to the hardware design of integrated circuits. Modern VLSI designs are extremely complex with several million parts and a product development time of 3 years [Whitney, 1996]. The design process is normally separated into a component design and a system design stage. At component design stage, single functions are designed and verified. At system design stage, components are aggregated and the whole system behavior and functionality is tested through simulation. In general, a complete verification is impossible. Hence, a systematic approach as exemplified for the PLC program design may impact the logical hardware design.可编程控制器1、前言可编程序的逻辑控制器（PLC），是由Richard E.Morley 于1968年发明的，如今已经被广泛的应用于生产、运输、化学等工业中。

(完整版)PLC英文文献+翻译

自动化专业本科毕业设计英文翻译学院(部)：专业班级：学生姓名：指导教师：年月日Programmable Logic ControllerONE：PLC overviewProgrammable controller is the first in the late 1960s in the United States, then called PLC programmable logic controller (Programmable Logic Controller) is used to replace relays. For the implementation of the logical judgment, timing, sequence number, and other control functions. The concept is presented PLC General Motors Corporation. PLC and the basic design is the computer functional improvements, flexible, generic and other advantages and relay control system simple and easy to operate, such as the advantages of cheap prices combined controller hardware is standard and overall. According to the practical application of target software in order to control the content of the user procedures memory controller, the controller and connecting the accused convenient target.In the mid-1970s, the PLC has been widely used as a central processing unit microprocessor, import export module and the external circuits are used, large-scale integrated circuits even when the Plc is no longer the only logical (IC) judgment functions also have data processing, PID conditioning and data communications functions. International Electro technical Commission (IEC) standards promulgated programmable controller for programmable controller draft made the following definition : programmable controller is a digital electronic computers operating system, specifically for applications in the industrial design environment. It used programmable memory, used to implement logic in their internal storage operations, sequence control, timing, counting and arithmetic operations, such as operating instructions, and through digital and analog input and output, the control of various types of machinery or production processes. Programmable controller and related peripherals, and industrial control systems easily linked to form a whole, to expand its functional design. Programmable controller for the user, is a non-contact equipment, the procedures can be changed to change production processes. The programmable controller has become a powerful tool for factory automation, widely popular replication.Programmable controller is user-oriented industries dedicated control computer, with many distinctive features.First, high reliability, anti-interference capability;Second，programming visual, simple;Third, adaptability good;Fourth functional improvements, strong functional interface. TWO：History of PLCProgrammable Logic Controllers (PLC), a computing device invented by Richard E. Morley in 1968, have been widely used in industry including manufacturing systems, transportation systems, chemical process facilities, and many others. At that time, the PLC replaced the hardwired logic with soft-wired logic or so-called relay ladder logic (RLL), a programming language visually resembling the hardwired logic, and reduced thereby the configuration time from 6 months down to 6 days [Moody and Morley, 1999].Although PC based control has started to come into place, PLC based control will remain the technique to which the majority of industrial applications will adhere due to its higher performance, lower price, and superior reliability in harsh environments. Moreover, according to a study on the PLC market of Frost and Sullivan [1995], an increase of the annual sales volume to 15 million PLC per year with the hardware value of more than 8 billion US dollars has been predicted, though the prices of computing hardware is steadily dropping. The inventor of the PLC, Richard E Morley, fairly considers the PLC market as a 5-billion industry at the present time.Though PLCs are widely used in industrial practice, the programming of PLC based control systems is still very much relying on trial-and-error. Alike software engineering, PLC software design is facing the software dilemma or crisis in a similar way. Morley himself emphasized this aspect most forcefully by indicatingIf houses were built like software projects, a single woodpecker could d estroy civilization.”Particularly, practical problems in PLC programming are to eliminate software bugs and to reduce the maintenance costs of old ladderlogic programs. Though the hardware costs of PLC are dropping continuously, reducing the scan time of the ladder logic is still an issue in industry so that low-cost PLC can be used.In general, the productivity in generating PLC is far behind compared to other domains, for instance, VLSI design, where efficient computer aided design tools are in practice. Existent software engineering methodologies are not necessarily applicable to the PLC based software design because PLC-programming requires a simultaneous consideration of hardware and software. The software design becomes, thereby, more and more the major cost driver. In many industrial design projects, more than of the manpower allocated for the control system design and installation is scheduled for testing and debugging PLC programs.In addition, current PLC based control systems are not properly designed to support the growing demand for flexibility and reconfigurability of manufacturing systems. A further problem, impelling the need for a systematic design methodology, is the increasing software complexity in large-scale projects.The objective of this thesis is to develop a systematic software design methodology for PLC operated automation systems. The design methodology involves high-level description based on state transition models that treat automation control systems as discrete event systems, a stepwise design process, and set of design rules providing guidance and measurements to achieve a successful design. The tangible outcome of this research is to find a way to reduce the uncertainty in managing the control software development process, that is, reducing programming and debugging time and their variation, increasing flexibility of the automation systems, and enabling software reusability through modularity. The goal is to overcome shortcomings of current programming strategies that are based on the experience of the individual software developer. Three：now of PLCFrom the structure is divided into fixed PLC and Module PLC, the two kinds of PLC including CPU board, I/O board, display panel, memory block, power, these elements into a do not remove overall. Module type PLC including CPU module, I/O modules, memory, thepower modules, bottom or a frame, these modules can be according to certain rules combination configuration.In the user view, a detailed analysis of the CPU's internal unnecessary, but working mechanism of every part of the circuit. The CPU control works, by it reads CPU instruction, interprets the instruction and executes instructions. But the pace of work by shock signal control.Unit work under the controller command used in a digital or logic operations.In computing and storage register of computation result, it is also among the controller command and work. CPU speed and memory capacity is the important parameters fot PLC . its determines the PLC speed of work, IO PLC number and software capacity, so limits to control size.Central Processing Unit (CPU) is the brain of a PLC controller. CPU itself is usually one of the microcontrollers. Aforetime these were 8-bit microcontrollers such as 8051, and now these are 16-and 32-bit microcontrollers. Unspoken rule is that you’ll find mostly Hitachi and Fujicu microcontrollers in PLC controllers by Japanese makers, Siemens in European controllers, and Motorola microcontrollers in American ones. CPU also takes care of communication, interconnectedness among other parts of PLC controllers, program execution, memory operation, overseeing input and setting up of an output.System memory (today mostly implemented in FLASH technology) is used by a PLC for a process control system. Aside form. this operating system it also contains a user program translated foram ladder diagram to a binary form. FLASH memory contents can be changed only in case where user program is being changed. PLC controllers were used earlier instead of PLASH memory and have had EPROM memory instead of FLASH memory which had to be erased with UV lamp and programmed on programmers. With the use of FLASH technology this process was greatly shortened. Reprogramming a program memory is done through a serial cable in a program for application development.User memory is divided into blocks having special functions. Some parts of a memory are used for storing input and output status. The real status of an input is stored either as “1”or as “0”in a specific memory bit/each input or output has one corresponding bit in memory. Other parts of memory are used to store variable contents for variables used in used program. For example, time value, or counter value would be stored in this part of the memory.PLC controller can be reprogrammed through a computer (usual way), but also through manual programmers (consoles). This practically means that each PLC controller can programmed through a computer if you have the software needed for programming. Today’s transmission computers are ideal for reprogramming a PLC controller in factory itself. This is of great importance to industry. Once the system is corrected, it is also important to read the right program into a PLC again. It is also good to check from time to time whether program in a PLC has not changed. This helps to avoid hazardous situations in factory rooms (some automakers have established communication networks which regularly check programs in PLC controllers to ensure execution only of good programs).Almost every program for programming a PLC controller possesses various useful options such as: forced switching on and off of the system input/outputs (I/O lines), program follow up in real time as well as documenting a diagram. This documenting is necessary to understand and define failures and malfunctions. Programmer can add remarks, names of input or output devices, and comments that can be useful when finding errors, or with system maintenance. Adding comments and remarks enables any technician (and not just a person who developed the system) to understand a ladder diagram right away. Comments and remarks can even quote precisely part numbers if replacements would be needed. This would speed up a repair of any problems that come up due to bad parts. The old way was such that a person who developed a system had protection on the program, so nobody aside from this person could understand how it was done. Correctly documented ladder diagram allows any technician to understand thoroughly how system functions.Electrical supply is used in bringing electrical energy to central processing unit. Most PLC controllers work either at 24 VDC or 220V AC. On some PLC controllers you’ll find electrical supply as a separatemodule. Those are usually bigger PLC controllers, while small and medium series already contain the supply module. User has to determine how much current to take from I/O module to ensure that electrical supply provides appropriate amount of current. Different types of modules use different amounts of electrical current.This electrical supply is usually not used to start external input or output. User has to provide separate supplies in starting PLC controller inputs because then you can ensure so called “pure” supply for the PLC controller. With pure supply we mean supply where industrial environment can not affect it damagingly. Some of the smaller PLC controllers supply their inputs with voltage from a small supply source already incorporated into a PLC.Four：PLC design criteriaA systematic approach to designing PLC software can overcome deficiencies in the traditional way of programming manufacturing control systems, and can have wide ramifications in several industrial applications. Automation control systems are modeled by formal languages or, equivalently, by state machines. Formal representations provide a high-level description of the behavior of the system to be controlled. State machines can be analytically evaluated as to whether or not they meet the desired goals. Secondly, a state machine description provides a structured representation to convey the logical requirements and constraints such as detailed safety rules. Thirdly, well-defined control systems design outcomes are conducive to automatic code generation- An ability to produce control software executable on commercial distinct logic controllers can reduce programming lead-time and labor cost. In particular, the thesis is relevant with respect to the following aspects.In modern manufacturing, systems are characterized by product and process innovation, become customer-driven and thus have to respond quickly to changing system requirements. A major challenge is therefore to provide enabling technologies that can economically reconfigure automation control systems in response to changing needs and new opportunities. Design and operational knowledge can be reused inreal-time, therefore, giving a significant competitive edge in industrial practice.Studies have shown that programming methodologies in automation systems have not been able to match rapid increase in use of computing resources. For instance, the programming of PLC still relies on a conventional programming style with ladder logic diagrams. As a result, the delays and resources in programming are a major stumbling stone for the progress of manufacturing industry. Testing and debugging may consume over 50% of the manpower allocated for the PLC program design. Standards [IEC 60848, 1999; IEC-61131-3, 1993; IEC 61499, 1998; ISO 15745-1, 1999] have been formed to fix and disseminate state-of-the-art design methods, but they normally cannot participate in advancing the knowledge of efficient program and system design.A systematic approach will increase the level of design automation through reusing existing software components, and will provide methods to make large-scale system design manageable. Likewise, it will improve software quality and reliability and will be relevant to systems high security standards, especially those having hazardous impact on the environment such as airport control, and public railroads.The software industry is regarded as a performance destructor and complexity generator. Steadily shrinking hardware prices spoils the need for software performance in terms of code optimization and efficiency. The result is that massive and less efficient software code on one hand outpaces the gains in hardware performance on the other hand. Secondly, software proliferates into complexity of unmanageable dimensions; software redesign and maintenance-essential in modern automation systems-becomes nearly impossible. Particularly, PLC programs have evolved from a couple lines of code 25 years ago to thousands of lines of code with a similar number of 1/O points. Increased safety, for instance new policies on fire protection, and the flexibility of modern automation systems add complexity to the program design process. Consequently, the life-cycle cost of software is a permanently growing fraction of the total cost. 80-90% of these costs are going into software maintenance, debugging, adaptation and expansion to meet changing needs.Today, the primary focus of most design research is based on mechanical or electrical products. One of the by-products of this proposed research is to enhance our fundamental understanding of design theory and methodology by extending it to the field of engineering systems design. A system design theory for large-scale and complex system is not yet fully developed. Particularly, the question of how to simplify a complicated or complex design task has not been tackled in a scientific way. Furthermore, building a bridge between design theory and the latest epistemological outcomes of formal representations in computer sciences and operations research, such as discrete event system modeling, can advance future development in engineering design.From a logical perspective, PLC software design is similar to the hardware design of integrated circuits. Modern VLSI designs are extremely complex with several million parts and a product development time of 3 years [Whitney, 1996]. The design process is normally separated into a component design and a system design stage. At component design stage, single functions are designed and verified. At system design stage, components are aggregated and the whole system behavior and functionality is tested through simulation. In general, a complete verification is impossible. Hence, a systematic approach as exemplified for the PLC program design may impact the logical hardware design.可编程控制器一、PLC概述可编程控制器是60年代末在美国首先出现的，当时叫可编程逻辑控制器PLC（Programmable Logic Controller），目的是用来取代继电器。

plc单片机毕业论文文献翻译中英文对照

外文翻译：The monolithic In order to prevent without authorization the visit or the copy monolithic integrated circuit machine in the procedure, the majority of monolithic integrated circuits all has the encryption to lock the localization or the encryption byte, by protects the internal procedure. If in programming time encrypts locks the localization to enable (locking), is unable with the ordinary programming directly reading in the monolithic integrated circuit the procedure, this is the so-called copy protection or says the fixed function. In fact, such protective measures are very frail, is very easily explained. The monolithic integrated circuit aggressor with the aid of the special purpose equipment or the self-made equipment, using the monolithic integrated circuit chip design in loophole or the software flaw, through the many kinds of technical method, may withdraw the essential information from the chip, gains in the monolithic integrated circuit the procedure. Therefore, has the newest technology extremely as electronic products project engineer which the essential understanding current monolithic integrated circuit attacks, achieves knows oneself and the other side, knows fairly well, can effectively prevent oneself spends the product which the massive moneys and the time laboriously designs the matter occurrence which is counterfeited by a others night between.monolithic integrated circuits attacks technology：At present, attacks the monolithic integrated circuit mainly to have four kind of technologies, respectively is:This technical usual use processor correspondence connection and in the use agreement, the encryption algorithm or these algorithm security loophole carries on the attack. The software attack obtains the success a case in point is to early A T M E L A the T 89 C series monolithic integrated circuit attack. The aggressor has used in this series monolithic integrated circuit cleaning operation succession design loophole, uses from arranges the procedure to lock the localization after the cleaning encryption, stops the next step of cleaning internal program memory data the operation, thus makes to add the dense monolithic integrated circuit not to turn the encryption monolithic integrated circuit, then use programming read-out internal procedure.This technology usually monitors the processor by the high time resolution when the normal operation all power sources and the connection connection simulation characteristic, and through monitors its electromagnetic radiation characteristic to implement the attack. Because the monolithic integrated circuit is an active electronic device, when it carries out the different instruction, the corresponding mains input consumption also correspondingly changes. Like this analyzes and examines these changes through the use special electronic surveying instrument and mathematics statistical method, then gains in the monolithic integrated circuit the specific essential information.the mistake has the technology This technical use exceptionally working condition causes the processor to make a mistake, then provides the extra visit to carry on the attack. Uses the most widespread mistake to have the attack method including the voltage impact and the clock impact. The low voltage and the high voltage attack may usefor to forbid the protection circuit work or to fortected the information. The power source and the clock transient state jump may affect the single scroll instruction in certain processors the decoding and the ece the processor to carry out the misoperation. Perhaps the clock transient state jump can reposition the protection circuit but not to be able to destroy is proxecution.This technology is the direct exposed chip interior segment, then the observation, holds controls, disturbs the monolithic integrated circuit by to achieve the attack goal.In order to facilitate in order to, the people divide into above four kind of attacks technology two kinds, a kind is the invasion attack (physical attack), this kind of attack needs to destroy the seal, then with the aid of the semiconductor test facility, the microscope and the micro locator, several hours even several week time can complete on the special laboratory flower. All micro probes technology all belongs to the invasion attack. Moreover three methods belong to the non- invasion attack, the monolithic integrated circuit which attacks cannot by the physical damage. In certain situation non- invasion attacks is specially dangerous, this is because the non- invasion attack needs the equipment usually to be possible the self-restraint and the promotion, therefore is extremely inexpensive.The majority of non- invasions attack needs the aggressor to have the good processor knowledge and the software knowledge. Is opposite with it, the invasion probe attack then does not need too many initial knowledge,moreover usually may use the one whole set similar technology to cope with the width scope the product. Therefore, the attack often starts to the monolithic integrated circuit from the invasion reverse engineering, the accumulation experience is helpful to the development more inexpensive and the fast non- invasion attack technology.Last step will be seeks the protection melt silk the position and protects the melt silk to expose under the ultraviolet ray. With enlargement factor at least 100 time of microscopes, inputs the foot from the programming voltage the segment to track generally, seeks the protection melt silk.This technical use exceptionally working condition causes the processor to make a mistake, then provides the extra visit to carry on the attack. Uses the most widespread mistake to have the attack method including the voltage impact and the clock impact. The low voltage and the high voltage attack may use for to forbid the protection circuit work or to force the processor to carry out the misoperation. Perhaps the clock transient state jump can reposition the protection circuit but not to be able to destroy is protected the information. The power source and the clock transient state jump may affect the single scroll instruction in certain processors the decoding and the execution.(4) probe technologyThis technology is the direct exposed chip interior segment, then the observation, holds controls, disturbs the monolithic integrated circuit by to achieve the attack goal.In order to facilitate in order to, the people divide into above four kindof attacks technology two kinds, a kind is the invasion attack (physical attack), this kind of attack needs to destroy the seal, then with the aid of the semiconductor test facility, the microscope and the micro locator, several hours even several week time can complete on the special laboratory flower. All micro probes technology all belongs to the invasion attack. Moreover three methods belong to the non- invasion attack, the monolithic integrated circuit which attacks cannot by the physical damage. In certain situation non- invasion attacks is specially dangerous, this is because the non- invasion attack needs the equipment usually to be possible the self-restraint and the promotion, therefore is extremely inexpensive.The majority of non- invasions attack needs the aggressor to have the good processor knowledge and the software knowledge. Is opposite with it, the invasion probe attack then does not need too many initial knowledge,moreover usually may use the one whole set similar technology to cope with the width scope the product. Therefore, the attack often starts to the monolithic integrated circuit from the invasion reverse engineering, the accumulation experience is helpful to the development more inexpensive and the fast non- invasion attack technology.3 invasions attacks general process：The invasion attack first step uncovers the chip seal. Some two methods may achieve this goal: The first kind is dissolves the chip seal completely, the exposed metal segment. The second kind is only moves above the silicon nucleus plastic seal. The first method needs the chip to tests on the jig, with the aid of Taiwan to operate. The second method except needs to have the aggressor certain knowledge and Wants outside skill, but also needs individual wisdom and the patience, but operates relatively quite is convenient.Above the chip plastic may use the knife to open, around the chip epoxy resin may use the aqua fortis perish. The hot aqua fortis can dissolve the chip seal but not to be able to affect the chip and the segment. This process carries on generally under the extremely dry condition, because the water existence possibly can corrode already the aluminum wire connection which exposes.Then first uses the acetone in the supersonic pond to clean this chip by except the remaining nitric acid, then cleans with the clear water by and is dry except the salinity. Not the supersonic pond, jumps over generally this step. In this kind of situation, the chip surface can a little dirty, but not too affects the ultraviolet ray to the chip operation effect.Last step will be seeks the protection melt silk the position and protects the melt silk to expose under the ultraviolet ray. With enlargement factor at least 100 time of microscopes, inputs the foot from the programming voltage the segment to track generally, seeks the protection melt silk.If does not have the microscope, then uses the chip different partially exposes to the ultraviolet ray under and the observed result way carries on the simple search. When operation applies not the opaque slip of paper cover chipby to protect the program memory not by the ultraviolet ray cleaning. Will protect the melt silk to expose in the ultraviolet ray next 5 ~ 10 minutes can broken the protection position protective function, afterwards, will use the simple programming to be possible the direct readout program memory content.Regarding used the protective layer to protect E E P R O the M unit the monolithic integrated circuit to say that, the use ultraviolet ray repositioned the protection circuit is not feasible. Regarding this kind of type monolithic integrated circuit, uses the micro probe technology reading the memory content generally. Opens after the chip seal, puts in the chip under the microscope to be able very easy finding中文翻译单片机为了防止未经授权访问或拷贝单片机的机内程序，大部分单片机都带有加密锁定位或者加密字节，以保护片内程序。

PLC的发展方向外文文献翻译、中英文翻译

外文资料The development direction of PLC:One is the development of the PLC operation in the direction of simplification.At present, one of the difficulties of PLC popularization is that the complicated programming makes the user prohibitive, and all programming languages of PLC are not the same in different manufacturers. Users often need to master more programming languages, which are difficult to control. Pid control, network communication, and so on. The programming and application of high speed counter, position control, data recording, formula and text display are also the difficulties in PLC programming. When programming them with common methods, we need to be familiar with the meaning of the special memory. They are assigned values at programming time and are accessed by the runtime to achieve corresponding functions. These programs also tend to have to do with interruptions. The process is cumbersome and error-prone, which hinders the further application of PLC. The development of PLC is bound to simplify the programming of complex tasks. At this point, Siemens acts as the forerunner, and only needs to input some parameters in the dialog box. Automatic generation of user programs, including interrupt programs, greatly facilitate the use of users.Second, PLC to high performance miniaturization direction development.PLC's function is getting richer and richer, and the volume is getting smaller and smaller. For example, Mitsubishi's FX-IS series PLC, the smallest type of machine, is only 60 × 90 × 75mm in volume, equivalent to a relay, but it has the ability to count at high speed, slope, alternate output and 16-bit four-bit operation, etc. It also has the adjustable potentiometer time setting function. PLC is no longer the early product that can only perform the logic operation of the switch quantity, but it has more and more powerful analog processing ability. And other advanced processing capabilities that used to be available only on computers, such as floating-point operations such as pid control, temperature control, precision Positioning, step drive, report statistics and so on. In this sense, the difference between PLC system and DCS (distributed Controlsystem) is becoming smaller and smaller. A process control system can also be constructed by using PLC.Third, the development of PLC network technology.There are two trends: on the one hand, the PLC network system is no longer a self-contained system, but is rapidly developing to an open system. In addition to forming its own characteristic PLC network system, the major brand PLC can also connect with the upper computer management system to achieve information communication and become a whole. Part of the information management system; on the other hand, field bus technology is widely used, PLC and other intelligent equipment installed on the site, such as intelligent instruments, sensors, intelligent solenoid valves, intelligent drive actuators, and so on, through a transmission medium (like twisted pair) Wires, coaxial cables, optical cables) link together and transmit information to each other according to the same communication protocol, thus forming a field network, which is more flexible in configuration, more convenient in expansion, and cheaper in cost than the simple PLC remote network. Performance price ratio is better, also more open meaning.Fourth, embedded PLC has a great space for development.The development of embedded PLC is diversified and has good performance at home and abroad: the netPLC, which combines fieldbus technology and PLC technology, introduced by Heuxun, Germany, has its own characteristics; A few years ago in China, Huazhong University of Science and Technology loaded embedded PLC system software into the EASYCORE1.00 core chipset as a hardware platform. The embedded PLC with multi-mode human channel is developed, and another development path is to develop the hardware / software integration of PLC and man-machine interface, which makes full use of case tools. Combined with the development platform and input of all kinds of embedded chips The hardware circuit library of the output channel is specially designed for developing customized PLC with ODM property for electromechanical equipment.The development space of embedded PLC in our country lies in the fact that it is very helpful to bring into full play the two characteristics of the development of automation industry in our country: there is a very strong market foundation for supporting electromechanical equipment, and it has enough, The best design and development team in the world. We can replace the universal PLC with the lowest cost, higher quality and custom-made design and production of embedded PLC.At the same time, the hardware, software, man-machine interface, communication and other aspects of embedded PLC function design is flexible, easy to cut, more close to the requirements of various grades of mechanical and electrical equipment. Embedded PLC is completely based on the technical foundation of embedded system. It can be used as .SOC chip, embedded operating system and programming environment that accords with EC61131-3 programming language standard, which makes it easy to find in the market.中文译文PLC的发展方向：一是PLC操作向简易化方向发展。

(完整版)PLC毕业设计的外文文献(及翻译)

PLC technique discussion and future developmentT.J.byersElectronic Test Equipment-principles and ApplicationsPrinceton University .AmericaAlong with the development of the ages, the technique that is nowadays is also gradually perfect, the competition plays more strong; the operation that list depends the artificial has already can't satisfied with the current manufacturing industry foreground, also can't guarantee the request of the higher quantity and high new the image of the technique business enterprise.The people see in produce practice, automate brought the tremendous convenience and the product quantities for people up of assurance, also eased the personnel's labor strength, reduce the establishment on the personnel. The target control of the hard realization in many complicated production lines, whole and excellent turn, the best decision etc, well-trained operation work, technical personnel or expert, governor but can judge and operate easily, can acquire the satisfied result. The research target of the artificial intelligence makes use of the calculator exactly to carry out, imitate these intelligences behavior, moderating the work through person's brain and calculators, with the mode that person's machine combine, for resolve the very complicated problem to look for the best path.We come in sight of the control that links after the electric appliances in various situation, that is already the that time generation past, now of after use in the mold a perhaps simple equipments of grass-roots control that the electric appliances can do for the low level only; And the PLC emergence also became the epoch-making topic, adding the vivid software control through a very and stable hardware, making the automation head for the new high tide.The PLC biggest characteristics lie in: The electrical engineering teacher already no longer electric hardware up too many calculations of cost, as long as order the importation that the button switch or the importation of the sensors order to link the PLC up can solve problem, pass to output to order the conjunction contact machine or control the start equipments of the big power after the electric appliances, but the exportation equipmentsdirect conjunction of the small power can.PLC internal containment have the CPU of the CPU, and take to have an I/ O for expand of exterior to connect a people's address and saving machine three big pieces to constitute, CPU core is from an or many is tired to add the machine to constitute, mathematics that they have the logic operation ability, and can read the procedure save the contents of the machine to drive the homologous saving machine and I/ Os to connect after pass the calculation; The I/ O add inner part is tired the input and output system of the machine and exterior link, and deposit the related data into the procedure saving machine or data saving machine; The saving machine can deposit the data that the I/ O input in the saving machine, and in work adjusting to become tired to add the machine and I/ Os to connect, saving machine separately saving machine RAM of the procedure saving machine ROM and dates, the ROM can do deposit of the data permanence in the saving machine, but RAM only for the CPU computes the temporary calculation usage of hour of buffer space.The PLC anti- interference is very and excellent, our root need not concern its service life and the work situation bad, these all problems have already no longer become the topic that we fail, but stay to our is a concern to come to internal resources of make use of the PLC to strengthen the control ability of the equipments for us, make our equipments more gentle.PLC language is not we imagine of edit collected materials the language or language of Cs to carry on weaving the distance, but the trapezoid diagram that the adoption is original after the electric appliances to control, make the electrical engineering teacher while weaving to write the procedure very easy comprehended the PLC language, and a lot of non- electricity professional also very quickly know and go deep into to the PLC.Is PLC one of the advantage above and only, this is also one part that the people comprehend more and easily, in a lot of equipments, the people have already no longer hoped to see too many control buttons, they damage not only and easily and produce the artificial error easiest, small is not a main error perhaps you can still accept; But lead even is a fatal error greatly is what we can't is tolerant of. New technique always for bringing more safe and convenient operation for us, make we a lot of problems for face on sweep but light, do you understand the HMI? Says the HMI here you basically not clear what it is, also have no interest understanding, change one inside text explains it into the touch to hold orman-machine interface you knew, it combines with the PLC to our larger space.HMI the control not only is reduced the control press button, increase the vivid of the control, more main of it is can sequence of, and at can the change data input to output the feedback with data, control in the temperature curve of imitate but also can keep the manifestation of view to come out. And can write the function help procedure through a plait to provide the help of various what lies in one's power, the one who make operate reduces the otiose error. Currently the HMI factory is also more and more, the function is also more and more strong, the price is also more and more low, and the noodles of the usage are wide more and more. The HMI foreground can say that think to be good.At a lot of situations, the list is a smooth movement that can't guarantee the equipments by the control of the single machine, but pass the information exchanges of the equipments and equipments to attain the result that we want. For example fore pack and the examination of the empress work preface, we will arrive wrapping information feedback to examine the place, and examine the information of the place to also want the feedback to packing. Pass the information share thus to make both the chain connect, becoming a total body, the match of your that thus make is more close, at each other attain to reflect the result that mutually flick.The PLC correspondence has already come more body now its value, at the PLC and correspondence between Places, can pass the communication of the information and the share of the data’s to guarantee that of the equipments moderates mutually, the result that arrive already to repair with each other. Data conversion the adoption RS232 between PLC connect to come to the transmission data, but the RS232 pick up a people and can guarantee 10 meters only of deliver the distance, if in the distance of 1000 meters we can pass the RS485 to carry on the correspondence, the longer distance can pass the MODEL only to carry on deliver.The PLC data transmission is just to be called a form to it in a piece of and continuous address that the data of the inner part delivers the other party, we, the PLC of the other party passes to read data in the watch to carry on the operation. If the data that data in the watch is a to establish generally, that is just the general data transmission, for example today of oil price rise, I want to deliver the price of the oil price to lose the oil ally on board, that is the share of the data; But take data in the watch for an instruction procedure that controls the PLC, that had the difficulty very much, for example you have to control one pedestal robot to pressthe action work that you imagine, you will draw up for it the form that a procedure combine with the data sends out to pass by.The form that information transport contain single work, the half a work and the difference of a workers .The meaning of the single work also is to say both, a can send out only, but a can receive only, for example a spy he can receive the designation of the superior only, but can't give the superior reply; A work of half is also 2 and can send out similar to accept the data, but can't send out and accept at the same time, for example when you make a phone call is to can't answer the phone, the other party also; But whole pair works is both can send out and accept the data, and can send out and accept at the same time. Be like the Internet is a typical example.The process that information transport also has synchronous and different step cent: The data line and the clock lines are synchronous when synchronous meaning lie in sending out the data, is also the data signal and the clock signals to be carry on by the CPU to send out at the same time, this needs to all want the specialized clock signal each other to carry on the transmission and connect to send, and is constrained, the characteristics of this kind of method lies in its speed very quick, but correspond work time of take up the CPU and also want to be long oppositely, at the same time the technique difficulty also very big. Its request lies in canting have an error margins in a dates deliver, otherwise the whole piece according to compare the occurrence mistake, this on the hardware is a bigger difficulty. Applied more and more extensive in some appropriative equipments, be like the appropriative medical treatment equipments, the numerical signal equipments...etc., in compare the one data deliver, its result is very good.And the different step is an application the most extensive, this receive benefit in it of technique difficulty is opposite and want to be small, at the same time not need to prepare the specialized clock signal, its characteristics to lie in, its data is partition, the long-lost send out and accept, be the CPU is too busy of time can grind to a stop sex to work, also reduced the difficulty on the hardware, the data throw to lose at the same time opposite want to be little, we can pass the examination of the data to observe whether the data that we send out has the mistake or not, be like strange accidentally the method, tired addition and eight efficacies method etc, can use to helps whether the data that we examine to send out have or not themistake occurrence, pass the feedback to carry on the discriminator.A line of transmission of the information contains a string of and combines the cent of: The usual PLC is 8 machines, certainly also having 16 machines. We can be at the time of sending out the data a send out to the other party, also can be 88 send out the data to the other party, and 8 differentiations are also the as that we say to send out the data and combine sends out the data. A speed is more and slowly, but as long as 2 or three lines can solve problem, and can use the telephone line to carry on the long range control. But combine the ocular transmission speed is very quick of, it is a string of ocular of 25600%, occupy the advantage in the short distance, the in view of the fact TTL electricity is even, being limited by the scope of one meter generally, it combine unwell used for the data transmission of the long pull, thus the cost is too expensive.Under a lot of circumstances we are total to like to adopt the string to combine the conversion chip to carry on deliver, under this kind of circumstance not need us to carry on to deposited the machine to establish too and complicatedly, but carry on the data exchanges through the data transmission instruction directly, but is not a very viable way in the correspondence, because the PLC of the other party must has been wait for your data exportation at the time of sending out the data, it can't do other works.When you are reading the book, you hear someone knock on door, you stop to start up of affair, open the door and combine to continue with the one who knock on door a dialogue, the telephone of this time rang, you signal hint to connect a telephone, after connecting the telephone through, return overdo come together knock on door to have a conversation, after dialogue complete, you continue again to see your book, this kind of circumstance we are called the interruption to it, it has the authority, also having sex of have the initiative, the PLC had such function .Its characteristics lie in us and may meet the urgently abrupt affairs in the operation process of the equipments, we want to stop to start immediately up of work, the whereabouts manages the more important affair, this kind of circumstance is we usually meet of, PLC while carry out urgent mission, total will keep the current appearance first, for example the address of the procedure, CPU of tired add the machine data etc., be like to stick down which the book that we see is when we open the door the page or simply make a mark, because we treat and would still need to continue immediately after book of see the behind.The CPU always does the affair that should do according to our will, but your mistake of give it an affair, it also would be same to do, this we must notice.The interruption is not only a, sometimes existing jointly with the hour several inside break, break off to have the preferred Class, they will carry out the interruption of the higher Class according to person's request. This kind of breaks off the medium interruption to also became to break off the set. The Class that certainly breaks off is relevant according to various resources of CPU with internal PLC; also following a heap of capacity size of also relevant fasten.The contents that break off has a lot of kinds, for example the exterior break off, correspondence in of send out and accept the interruption and settle and the clock that count break off, still have the WDT to reset the interruption etc., they enriched the CPU to respond to the category while handle various business. Speak thus perhaps you can't comprehend the internal structure and operation orders of the interruption completely also, we do a very small example to explain.Each equipment always will not forget a button, it also is at we meet the urgent circumstance use of that is nasty to stop the button. When we meet the Human body trouble and surprised circumstances we as long as press it, the machine stops all operations immediately, and wait for processing the over surprised empress recover the operation again. Nasty stop the internal I/ O of the internal CPU of the button conjunction PLC to connect up, be to press button an exterior to trigger signal for CPU, the CPU carries on to the I/ O to examine again, being to confirm to have the exterior to trigger the signal, CPU protection the spot breaks off procedure counts the machine turn the homologous exterior I/ O automatically in the procedure to go to also, be exterior interruption procedure processing complete, the procedure counts the machine to return the main procedure to continue to work. Have 1:00 can what to explain is we generally would nasty stop the button of exterior break off to rise to the tallest Class, thus guarantee the safety.When we are work a work piece, giving the PLC a signal, counting PLC inner part the machine add 1 to compute us for a day of workload, a count the machine and can solve problem in brief, certainly they also can keep the data under the condition of dropping the electricity, urging the data not to throw to lose, this is also what we hope earnestly.The PLC still has the function that the high class counts the machine, being us while accept some dates of high speed, the high speed that here say is the data of the in all aspects tiny second class, for example the bar code scanner is scanning the data continuously, calculating high-speed signal of the data processor DSP etc., we will adopt the high class to count the machine to help we carry on count. It at the PLC carries out the procedure once discover that the high class counts the machine to should of interruption, will let go of the work on the hand immediately. The trapezoid diagram procedure that passes by to weave the distance again explains the high class for us to carry out procedure to count machine would automatic performance to should of work, thus rise the Class that the high class counts the machine to high one Class.You heard too many this phrases perhaps:" crash", the meaning that is mostly is a workload of CPU to lead greatly, the internal resources shortage etc. the circumstance can't result in procedure circulate. The PLC also has the similar circumstance, there is a watchdog WDT in the inner part of PLC, we can establish time that a procedure of WDT circulate, being to appear the procedure to jump to turn the mistake in the procedure movement process or the procedure is busy, movement time of the procedure exceeds WDT constitution time, the CPU turn but the WDT reset the appearance. The procedure restarts the movement, but will not carry on the breakage to the interruption.The PLC development has already entered for network ages of correspondence from the mode of the one, and together other works control the net plank and I/ O card planks to carry on the share easily. A state software can pass all se hardwires link, more animation picture of keep the view to carries on the control, and cans pass the Internet to carry on the control in the foreign land, the blast-off that is like the absolute being boat No.5 is to adopt this kind of way to make airship go up the sky.The development of the higher layer needs our continuous effort to obtain. The PLC emergence has already affected a few persons fully, we also obtained more knowledge and precepts from the top one experience of the generation, coming to the continuous development PLC technique, push it toward higher wave tide.可编程控制器技术讨论与未来发展T.J.拜尔斯（电子测试设备原理及应用普林斯顿大学）随着时代的发展，当今的技术也日趋完善、竞争愈演愈烈；单靠人工的操作已不能满足于目前的制造业前景，也无法保证更高质量的要求和高新技术企业的形象。

PLC的应用外文文献翻译、中英文翻译、外文翻译

Application of PLCPLC is one kind specially for the digital operation operation electronic installation which applies under the industry environment designs. It uses may the coding memory, uses for in its internal memory operation and so on actuating logic operation, sequence operation, time, counting and arithmetic operation instructions, and can through digital or the simulation-like input and the output, controls each type the machinery or the production process. PLC and the related auxiliary equipment should according to form a whole easy with the industrial control system, easy to expand its function the principle to design.”In the 1970s the last stage, the programmable controller entered the practical application development phase, the computer technology has introduced in comprehensively the programmable controller, causes its function to have the leap. The higher operating speed, the subminiature volume, the more reliable industry antijamming design, the simulation quantity operation, the PID function and the extremely high performance-to-price ratio has established it in the modern industry status. In the early-1980s, the programmable controller has obtained the widespread application in the advanced industrial nation. This time programmable controller develops the characteristic is large-scale, the high velocity, the high performance, the product seriation. This stage's another characteristic is in the world produces the programmable controller's country to increase day by day, the output rises day by day. This symbolizes that the programmable controller marched into the mature stage.The 20th century last stage, the programmable controller's development characteristic was even more adapts in the modern industry need. From the control scale, this time has developed the large-scale machinery and subminiature machine; From the control, was born various special function unit, used in the pressure, the temperature, the rotational speed, the displacement and so on all kinds of control situation; From product necessary ability, has produced each kind of man-machine contact surface unit, the correspondence unit, caused to apply the programmable controller's industrial control equipment necessary to be easier. At present, the programmable controller in domain and so on machine manufacture, petroleum chemical industry, metallurgy steel and iron, automobile, light industry applications obtained the considerable development.Our country programmable controller's introduction, applies, the development, the production to follow the reform and open policy to start. At first has used the programmable controller massively in the introduction equipment. Then expanded the PLC application unceasingly in each kind of enterprise's production equipment and the product. At present, our country have been possible to produce the middle and small scale programmable controller. East Shanghai the room electricity Limited company produces the CF series, Hangzhou engine bed electrical equipment factory production's DKK and D series, Dalian Aggregate machine-tool Research institute produces S series, the Suzhou Electronic accounting machine Factory production's YZ series and so on many kinds of products have had certain scale and have obtained the application in the manufactured products. In addition, the non-flowers of tin light company, Chinese-foreign joint ventures and so on Shanghai Township Island Company are also our country quite famous PLC Manufacturers. May anticipate that along with our country modernization process's thorough, PLC will have the broader application world in our country.Uses the manual operation in view of the YNL draw die machine electric control system, the existence operation is complex, the operation requests high, needs specially shortcomings and so on operators, has designed PLC the control system. Has given the electrical machinery main return route, the PLC periphery wiring diagram; Has established the systems operation trapezoidal chart and the instruction list; And to this system key element shaping. After the improvement control system has realized the entire system board process automation, not only raised the production efficiency, but also has saved the labor force, reduced the production cost, may obtain a greater economic efficiency.PLC的应用PLC是一种专门为在工业环境下应用而设计的数字运算操作的电子装置。

PLC外文文献中英

外文文献PLC technique discussion and future developmentAlong with the development of the ages, the technique that is nowadays is also gradually perfect, the competition plays more strong; the operation that list depends the artificial has already can't satisfied with the current manufacturing industry foreground, also can't guarantee the request of the higher quantity and high new the image of the technique business enterprise.The people see in produce practice, automate brought the tremendous convenience and the product quantities for people up of assurance, also eased the personnel's labor strength, reduce the establishment on the personnel. The target control of the hard realization in many complicated production lines, whole and excellent turn, the best decision etc., well-trained operation work, technical personnel or expert, governor but can judge and operate easily, can acquire the satisfied result. The research target of the artificial intelligence makes use of the calculator exactly to carry out, imitate these intelligences behavior, moderating the work through person's brain and calculators, with the mode that person's machine combine, for resolve the very complicated problem to look for the best pathWe come in sight of the control that links after the electric appliances in various situation, that is already the that time generation past, now of after use in the mold a perhaps simple equipments of grass-roots control that the electric appliances can do for the low level only; And the PLC emergence also became the epoch-making topic, adding the vivid software control through a very and stable hardware, making the automation head for the new high tide.The PLC biggest characteristics lie in: The electrical engineering teacher already no longer electric hardware up too many calculations of cost, as long as order the importation that the button switch or the importation of the sensors order to link the PLC up can solve problem, pass to output to order the conjunction contact machine or control the start equipments of the big power after the electric appliances, but the exportation equipments direct conjunction of the small power can.PLC internal containment have the CPU of the CPU, and take to have an I/ O for expand of exterior to connect a people's address and saving machine three big pieces to constitute, CPU core is from an or many is tired to add the machine to constitute, mathematics that they have the logic operation ability, and can read the procedure save the contents of the machine to drive the homologous saving machine and I/ Os to connect after pass the calculation; The I/ O add inner part is tired the input and output system of the machine and exterior link, and deposit the related data into the procedure saving machine or data saving machine; The saving machine can deposit the data that the I/ O input in the saving machine, and in work adjusting to become tired to add the machine and I/ Os to connect, saving machine separately saving machine RAM of the procedure saving machine ROM and dates, the ROM can dodeposit of the data permanence in the saving machine, but RAM only for the CPU computes the temporary calculation usage of hour of buffer space.The PLC anti- interference is very and excellent, our root need not concern its service life and the work situation bad, these all problems have already no longer become the topic that we fail, but stay to our is a concern to come to internal resources of make use of the PLC to strengthen the control ability of the equipments for us, make our equipments more gentle.PLC language is not we imagine of edit collected materials the language or language of Cs to carry on weaving the distance, but the trapezoid diagram that the adoption is original after the electric appliances to control, make the electrical engineering teacher while weaving to write the procedure very easy comprehended the PLC language, and a lot of non- electricity professional also very quickly know and go deep into to the PLC.Is PLC one of the advantage above and only, this is also one part that the people comprehend more and easily, in a lot of equipments, the people have already no longer hoped to see too many control buttons, they damage not only and easily and produce the artificial error easiest, small is not a main error perhaps you can still accept; But lead even is a fatal error greatly is what we can't is tolerant of. New technique always for bringing more safe and convenient operation for us, make we a lot of problems for face on sweep but light, do you understand the HMI? Says the HMI here you basically not clear what it is, also have no interest understanding, change one inside text explains it into the touch to hold or man-machine interface you knew, and it combines with the PLC to our larger space.HMI the control not only is reduced the control press button, increase the vivid of the control, more main of it is can sequence of, and at can the change data input to output the feedback with data, control in the temperature curve of imitate but also can keep the manifestation of view to come out. And can write the function help procedure through a plait to provide the help of various what lies in one's power, the one who make operate reduces the otiose error. Currently the HMI factory is also more and more, the function is also more and more strong, the price is also more and more low, and the noodles of the usage are wide more and more. The HMI foreground can say that think ° to be good very.At a lot of situations, the list is a smooth movement that can't guarantee the equipments by the control of the single machine, but pass the information exchanges of the equipments and equipments to attain the result that we want. For example fore pack and the examination of the empress work preface, we will arrive wrapping information feedback to examine the place, and examine the information of the place to also want the feedback to packing. Pass the information share thus to make both the chain connect, becoming a total body, the match of your that thus make is more close, at each other attain to reflect the result that mutually flick.The PLC correspondence has already come more body now its value, at the PLC and correspondence between PLCs, can pass the communication of the information and the share of the dates to guarantee that of the equipments moderates mutually, the result that arrive already to repair with each other. Data conversion the adoption RS232 between PLC connect to come to the transmission data, but the RS232 pick up a people and can guarantee 10 meters only of deliver the distance, if in the distance of 1000 meters we can pass the RS485 to carry on the correspondence, the longer distance can pass the MODEL only to carry on deliver.The PLC data transmission is just to be called a form to it in a piece of and continuous address that the data of the inner part delivers the other party, we, the PLC of the other party passes to read data in the watch to carry on the operation. If the data that data in the watch is a to establish generally, that is just the general data transmission, for example today of oil price rise, I want to deliver the price of the oil price to lose the oil ally on board, that is the share of the data; But take data in the watch for an instruction procedure that controls the PLC, that had the difficulty very much, for example you have to control one pedestal robot to press the action work that you imagine, you will draw up for it the form that a procedure combine with the data sends out to pass by.The form that information transport contain single work, the half a work and the difference of a workers .The meaning of the single work also is to say both, a can send out only, but a can receive only, for example a spy he can receive the designation of the superior only, but can't give the superior reply; A work of half is also 2 and can send out similar to accept the data, but can't send out and accept at the same time, for example when you make a phone call is to can't answer the phone, the other party also; But whole pair works is both can send out and accept the data, and can send out and accept at the same time. Be like the Internet is a typical example.The process that information transport also has synchronous and different step cent: The data line and the clock lines are synchronous when synchronous meaning lie in sending out the data, is also the data signal and the clock signals to be carry on by the CPU to send out at the same time, this needs to all want the specialized clock signal each other to carry on the transmission and connect to send, and is constrained, the characteristics of this kind of method lies in its speed very quick, but correspond work time of take up the CPU and also want to be long oppositely, at the same time the technique difficulty also very big. Its request lies in canting have an error margins in a dates deliver, otherwise the whole piece according to compare the occurrence mistake, this on the hardware is a bigger difficulty. Applied more and more extensive in some appropriative equipments, be like the appropriative medical treatment equipments, the numerical signal equipments...etc., in compare the one data deliver, its result is very good.And the different step is an application the most extensive, this receive benefit in it of technique difficulty is opposite and want to be small, at the same time not need to prepare the specialized clock signal, its characteristics to lie in, its data is partition, thelong-lost send out and accept, be the CPU is too busy of time can grind to a stop sex to work, also reduced the difficulty on the hardware, the data throw to lose at the same time opposite want to be little, we can pass the examination of the data to observe whether the data that we send out has the mistake or not, be like strange accidentally the method, tired addition and eight efficacies method etc., can use to helps whether the data that we examine to send out have or not the mistake occurrence, pass the feedback to carry on the discriminator.A line of transmission of the information contains a string of and combine the cent of: The usual PLC is 8 machines, certainly also having 16 machines. We can be an at the time of sending out the data a send out to the other party, also can be 88 send out the data to the other party, an and 8 differentiations are also the as that we say to send out the data and combine sends out the data. A speed is more and slowly, but as long as 2 or three lines can solve problem, and can use the telephone line to carry on the long range control. But combine the ocular transmission speed is very quick of, it is a string of ocular of 25600%, occupy the advantage in the short distance, the in view of the fact TTL electricity is even, being limited by the scope of one meter generally, it combine unwell used for the data transmission of the long pull, thus the cost is too expensive.Under a lot of circumstances we are total to like to adopt the string to combine the conversion chip to carry on deliver, under this kind of circumstance not need us to carry on to deposited the machine to establish too and complicatedly, but carry on the data exchanges through the data transmission instruction directly, but is not a very viable way in the correspondence, because the PLC of the other party must has been wait for your data exportation at the time of sending out the data, it can't do other works.When you are reading the book, you hear someone knock on door, you stop to start up of affair, open the door and combine to continue with the one who knock on door a dialogue, the telephone of this time rang, you signal hint to connect a telephone, after connecting the telephone through, return overdo come together knock on door to have a conversation, after dialogue complete, you continue again to see your book, this kind of circumstance we are called the interruption to it, it has the authority, also having sex of have the initiative, the PLC had such function .Its characteristics lie in us and may meet the urgently abrupt affairs in the operation process of the equipments, we want to stop to start immediately up of work, the whereabouts manages the more important affair, this kind of circumstance is we usually meet of, PLC while carry out urgent mission, total will keep the current appearance first, for example the address of the procedure, CPU of tired add the machine data etc., be like to stick down which the book that we see is when we open the door the page or simply make a mark, because we treat and would still need to continue immediately after book of see the behind. The CPU always does the affair that should do according to our will, but your mistake of give it an affair, it also would be same to do, this we must notice.The interruption is not only a, sometimes existing jointly with the hour severalinside break, break off to have the preferred Class, they will carry out the interruption of the higher Class according to person's request. This kind of breaks off the medium interruption to also became to break off the set. The Class that certainly break off is relevant according to various resources of CPU with internal PLC, also following a heap of capacity size of also relevant fasten.The contents that break off has a lot of kinds, for example the exterior break off, correspondence in of send out and accept the interruption and settle and the clock that count break off, still have the WDT to reset the interruption etc., they enriched the CPU to respond to the category while handle various business. Speak thus perhaps you can't comprehend the internal structure and operation orders of the interruption completely also, we do a very small example to explain.Each equipment always will not forget a button, it also is at we meet the urgent circumstance use of, which is nasty to stop the button. When we meet the Human body trouble and surprised circumstances we as long as press it, the machine stops all operations immediately, and wait for processing the over surprised empress recover the operation again. Nasty stop the internal I/ O of the internal CPU of the button conjunction PLC to connect up, be to press button an exterior to trigger signal for CPU, the CPU carries on to the I/ O to examine again, being to confirm to have the exterior to trigger the signal, CPU protection the spot breaks off procedure counts the machine turn the homologous exterior I/ O automatically in the procedure to go to also, be exterior interruption procedure processing complete, the procedure counts the machine to return the main procedure to continue to work. Have 1:00 can what to explain is we generally would nasty stop the button of exterior break off to rise to the tallest Class, thus guarantee the safety.When we are work a work piece, giving the PLC a signal, counting PLC inner part the machine add 1 to compute us for a day of workload, a count the machine and can solve problem in brief, certainly they also can keep the data under the condition of dropping the electricity, urging the data not to throw to lose, this is also what we hope earnestly.The PLC still has the function that the high class counts the machine, being us while accept some dates of high speed, the high speed that here say is the data of the in all aspects tiny second class, for example the bar code scanner is scanning the data continuously, calculating high-speed signal of the data processor DSP etc., we will adopt the high class to count the machine to help we carry on count. It at the PLC carries out the procedure once discover that the high class counts the machine to should of interruption, will let go of the work on the hand immediately. The trapezoid diagram procedure that passes by to weave the distance again explains the high class for us to carry out procedure to count machine would automatic performance to should of work, thus rise the Class that the high class counts the machine to high one Class.You heard too many this phrases perhaps:" crash", the meaning that is mostly isa workload of CPU to lead greatly, the internal resources shortage etc. the circumstance can't result in procedure circulate. The PLC also has the similar circumstance, there is a watchdog WDT in the inner part of PLC, we can establish time that a procedure of WDT circulate, being to appear the procedure to jump to turn the mistake in the procedure movement process or the procedure is busy, movement time of the procedure exceeds WDT constitution time, the CPU turn but the WDT reset the appearance. The procedure restarts the movement, but will not carry on the breakage to the interruption.The PLC development has already entered for network ages of correspondence from the mode of the one, and together other works control the net plank and I/ O card planks to carry on the share easily. A state software can pass all se hardwires link, more animation picture of keep the view to carries on the control, and cans pass the Internet to carry on the control in the foreign land, the blast-off that is like the absolute being boat No.5 is to adopt this kind of way to make airship go up the sky.The development of the higher layer needs our continuous effort to obtain. The PLC emergence has already affected a few persons fully, we also obtained more knowledge and precepts from the top one experience of the generation, coming to the continuous development PLC technique, push it toward higher wave tide.Knowing the available PLC network options and their best applications will ensure an efficient and flexible control system design.The programmable logic controller's (PLC's) ability to support a range of communication methods makes it an ideal control and data acquisition device for a wide variety of industrial automation and facility control applications. However, there is some confusion because so many possibilities exist. To help eliminate this confusion, let's list what communications are available and when they would be best applied.To understand the PLC's communications versatility, let's first define the terms used in describing the various systems.ASCII: This stands for "American Standard Code for Information Interchange." As shown in Fig. 1, when the letter "A" is transmitted, for instance, it's automatically coded as "65" by the sending equipment. The receiving equipment translates the "65" back to the letter "A." Thus, different devices can communicate with each other as long as both use ASCII code.ASCII module: This intelligent PLC module is used for connecting PLCs to other devices also capable of communicating using ASCII code as a vehicle.Bus topology: This is a linear local area network (LAN) arrangement, as shown in Fig. 2A, in which individual nodes are tapped into a main communications cable at a single point and broadcast messages. These messages travel in both directions on the bus from the point of connection until they are dissipated by terminators at each endof the bus.CPU: This stands for "central processing unit," which actually is that part of a computer, PLC, or other intelligent device where arithmetic and logical operations are performed and instructions are decoded and executed.Daisy chain: This is a description of the connection of individual devices in a PLC network, where, as shown in Fig. 3, each device is connected to the next and communications signals pass from one unit to the next in a sequential fashion.Distributed control: This is an automation concept in which portions of an automated system are controlled by separate controllers, which are located in close proximity to their area of direct control (control is decentralized and spread out over the system).Host computer: This is a computer that's used to transfer data to, or receive data from, a PLC in a PLC/computer network.Intelligent device: This term describes any device equipped with its own CPU.I/O: This stands for "inputs and outputs," which are modules that handle data to the PLC (inputs) or signals from the PLC (outputs) to an external device.Kbps: This stands for "thousand bits per second," which is a rate of measure for electronic data transfer.Mbps: This stands for "million bits per second."Node: This term is applied to any one of the positions or stations in a network. Each node incorporates a device that can communicate with all other devices on the network.Protocol: The definition of how data is arranged and coded for transmission on a network.Ring topology. This is a LAN arrangement, as shown in Fig. 2C, in which each node is connected to two other nodes, resulting in a continuous, closed, circular path or loop for messages to circulate, usually in one direction. Some ring topologies have a special "loop back" feature that allows them to continue functioning even if the main cable is severed.RS232. This is an IEEE standard for serial communications that describes specific wiring connections, voltage levels, and other operating parameters for electronic data communications. There also are several other RS standards defined.Serial: This is an electronic data transfer scheme in which information is transmitted one bit at a time.Serial port: This the communications access point on a device that is set up for serial communications.Star topology. This is a LAN arrangement in which, as shown in Fig. 2B, nodes are connected to one another through a central hub, which can be active or passive. An active hub performs network duties such as message routing and maintenance. A passive central hub simply passes the message along to all the nodes connected to it.Topology: This relates to a specific arrangement of nodes in a LAN in relation to one another.Transparent: This term describes automatic events or processes built into a system that require no special programming or prompting from an operator.Now that we're familiar with these terms, let's see how they are used in describing the available PLC network options.PLC network optionsPLC networks provide you with a variety of networking options to meet specific control and communications requirements. Typical options include remote I/O, peer-to-peer, and host computer communications, as well as LANs. These networks can provide reliable and cost-effective communications between as few as two or as many as several hundred PLCs, computers, and other intelligent devices.Many PLC vendors offer proprietary networking systems that are unique and will not communicate with another make of PLC. This is because of the different communications protocols, command sequences, error-checking schemes, and communications media used by each manufacturer.However, it is possible to make different PLCs "talk" to one another; what's required is an ASCII interface for the connection(s), along with considerable work with software.Remote I/0 systemsA remote I/O configuration, as shown in Fig. 4A, has the actual inputs and outputs at some distance from the controller and CPU. This type of system, which can be described as a "master-and-slave" configuration, allows many distant digital and analog points to be controlled by a single PLC. Typically, remote I/Os are connected to the CPU via twisted pair or fiber optic cables.Remote I/O configurations can be extremely cost-effective control solutions where only a few I/O points are needed in widely separated areas. In this situation, it's not always necessary, or practical for that matter, to have a controller at each site. Nor is it practical to individually hard wire each I/O point over long distances back to the CPU. For example, remote I/O systems can be used in acquiring data from remoteplant or facility locations. Information such as cycle times, counts, duration or events, etc. then can be sent back to the PLC for maintenance and management reporting.In a remote I/O configuration, the master controller polls the slaved I/O for its current I/O status. The remote I/O system responds, and the master PLC then signals the remote I/O to change the state of outputs as dictated by the control program in the PLC's memory. This entire cycle occurs hundreds of times per second.Peer-to-peer networksPeer-to-peer networks, as shown in Fig. 4B, enhance reliability by decentralizing the control functions without sacrificing coordinated control. In this type of network, numerous PLCs are connected to one another in a daisy-chain fashion, and a common memory table is duplicated in the memory of each. In this way, when any PLC writes data to this memory area, the information is automatically transferred to all other PLCs in the network. They then can use this information in their own operating programs.With peer-to-peer networks, each PLC in the network is responsible for its own control site and only needs to be programmed for its own area of responsibility. This aspect of the network significantly reduces programming and debugging complexity; because all communications occur transparently to the user, communications programming is reduced to simple read-and-write statements.In a peer-to-peer system, there's no master PLC. However, it's possible to designate one of the PLCs as a master for use as a type of group controller. This PLC then can be used to accept input information from an operator input terminal, for example, sending all the necessary parameters to other PLCs and coordinating the sequencing of various events.Host computer linksPLCs also can be connected with computers or other intelligent devices. In fact, most PLCs, from the small to the very large, can be directly connected to a computer or part of a multi drop host computer network via RS232C or RS422 ports. This combination of computer and controller maximizes the capabilities of the PLC, for control and data acquisition, as well as the computer, for data processing, documentation, and operator interface.In a PLC/computer network, as shown in Fig. 4C, all communications are initiated by the host computer, which is connected to all the PLCs in a daisy-chain fashion. This computer individually addresses each of its networked PLCs and asks for specific information. The addressed PLC then sends this information to the computer for storage and further analysis. This cycle occurs hundreds of times per second.Host computers also can aid in programming PLCs; powerful programming anddocumentation software is available for program development. Programs then can be written on the computer in relay ladder logic and downloaded into the PLC. In this way, you can create, modify, debug, and monitor PLC programs via a computer terminal.In addition to host computers, PLCs often must interface with other devices, such as operator interface terminals for large security and building management systems. Although many intelligent devices can communicate directly with PLCs via conventional RS232C ports and serial ASCII code, some don't have the software ability to interface with individual PLC models. Instead, they typically send and receive data in fixed formats. It's the PLC programmer's responsibility to provide the necessary software interface.The easiest way to provide such an interface to fixed-format intelligent devices is to use an ASCII/BASIC module on the PLC. This module is essentially a small computer that plugs into the bus of the PLC. Equipped with RS232 ports and programmed in BASIC, the module easily can handle ASCII communications with peripheral devices, data acquisition functions, programming sequences, "number crunching," report and display generation, and other requirements.Access, protocol, and modulation functions of LANsBy using standard interfaces and protocols, LANs allow a mix of devices (PLCs, PCs, mainframe computers, operator interface terminals, etc.) from many different vendors to communicate with others on the network.Access: A LAN's access method prevents the occurrence of more than one message on the network at a time. There are two common access methods.Collision detection is where the nodes "listen" to the network and transmit only if there are no other messages on the network. If two nodes transmit simultaneously, the collision is detected and both nodes retransmit until their messages get through properly.Token passing allows each node to transmit only if it's in possession of a special electronic message called a token. The token is passed from node to node, allowing each an opportunity to transmit without interference. Tokens usually have a time limit to prevent a single node from tying up the token for a long period of time.Protocol: Network protocols define the way messages are arranged and coded for transmission on the LAN. The following are two common types.Proprietary protocols are unique message arrangements and coding developed by a specific vendor for use with that vendor's product only.Open protocols are based on industry standards such as TCP/IP or ISO/OSI models and are openly published.。

PLC中英文对照外文翻译文献

中英文对照翻译外文资料:PLC technique discussion and future developmentAlong with the development of the ages, the technique that is nowadays is also gradually perfect, the competition plays more more strong; the operation that list depends the artificial has already can't satisfied with the current manufacturing industry foreground, also can't guarantee the request of the higher quantity and high new the image of the technique business enterprise.The people see in produce practice, automate brought the tremendous convenience and the product quantities for people up of assurance, also eased the personnel's labor strength, reduce the establishment on the personnel. The target control of the hard realization in many complicated production lines, whole and excellent turn, the best decision etc., well-trained operation work, technical personnel or expert, governor but can judge and operate easily, can acquire the satisfied result. The research target of the artificial intelligence makes use of the calculator exactly to carry out, imitate these intelligences behavior, moderating the work through person's brain and calculators, with the mode that person's machine combine, for resolve the very complicated problem to look for the best pathWe come in sight of the control that links after the electric appliances in various situation, that is already the that time generation past, now of after use in the mold a perhaps simple equipments of grass-roots control that the electric appliances can do for the low level only;And the PLC emergence also became the epoch-making topic, adding the vivid software control through a very and stable hardware, making the automation head for the new high tide.The PLC biggest characteristics lie in: The electrical engineering teacher already no longer electric hardware up too many calculationses of cost, as long as order the importation that the button switch or the importation of the sensors order to link the PLC up can solve problem, pass to output to order the conjunction contact machine or control the start equipments of thebig power after the electric appliances, but the exportation equipments direct conjunction of the small power can.PLC internal containment have the CPU of the CPU, and take to have an I/ O for expand of exterior to connect a people's address and saving machine three big pieces to constitute, CPU core is from an or many is tired to add the machine to constitute, mathematics that they have the logic operation ability, and can read the procedure save the contents of the machine to drive the homologous saving machine and I/ Os to connect after pass the calculation; The I/ O add inner part is tired the input and output system of the machine and exterior link, and deposit the related data into the procedure saving machine or data saving machine; The saving machine can deposit the data that the I/ O input in the saving machine, and in work adjusting to become tired to add the machine and I/ Os to connect, saving machine separately saving machine RAM of the procedure saving machine ROM and datas, the ROM can can do deposit of the data permanence in the saving machine, but RAM only for the CPU computes the temporary calculation usage of hour of buffer space.The PLC anti- interference is very and excellent, our root need not concern its service life and the work situation bad, these all problems have already no longer become the topic that we fail, but stay to our is a concern to come to internal resources of make use of the PLC to strengthen the control ability of the equipments for us, make our equipments more gentle. PLC language is not we imagine of edit collected materials the language or language of Cs to carry on weaving the distance, but the trapezoid diagram that the adoption is original after the electric appliances to control, make the electrical engineering teacher while weaving to write the procedure very easy comprehended the PLC language, and a lot of non- electricity professional also very quickly know and go deep into to the PLC.Is PLC one of the advantage above and only, this is also one part that the people comprehend more and easily, in a lot of equipmentses, the people have already no longer hoped to see too many control buttons, they damage not only and easily and produce the artificial error easiest, small is not a main error perhaps you can still accept; But lead even is a fatal error greatly is what we can't is tolerant of. New technique always for bringing more safe and convenient operation for us, make we a lot of problems for face on sweep but light, do you understand the HMI? Says the HMI here you basically not clear what it is, also have no interest understanding, change one inside text explains it into the touch to hold or man-machine interface you knew, it combines with the PLC to our larger space.HMI the control not only only is reduced the control press button, increase the vivid of the control, more main of it is can sequence of, and at can the change data input to output thefeedback with data, control in the temperature curve of imitate but also can keep the manifestation of view to come out. And can write the function help procedure through a plait to provide the help of various what lies in one's power, the one who make operate reduces the otiose error. Currently the HMI factory is also more and more, the function is also more and more strong, the price is also more and more low, the noodles of the usage are wide more and more. The HMI foreground can say that think ° to be good very.At a lot of situations, the list is is a smooth movement that can't guarantee the equipments by the control of the single machine, but pass the information exchanges of the equipments and equipments to attain the result that we want. For example fore pack and the examination of the empress work preface, we will arrive wrapping information feedback to examine the place, and examine the information of the place to also want the feedback to packing. Pass the information share thus to make both the chain connect, becoming a total body, the match of your that thus make is more close, at each other attain to reflect the result that mutually flick. The PLC correspondence has already come more more body now its value, at the PLC and correspondence between PLCs, can pass the communication of the information and the share of the datas to guarantee that of the equipments moderates mutually, the result that arrive already to repair with each other. Data conversion the adoption RS232 between PLC connect to come to the transmission data, but the RS232 pick up a people and can guarantee 10 meters only of deliver the distance, if in the distance of 1000 meters we can pass the RS485 to carry on the correspondence, the longer distance can pass the MODEL only to carry on deliver. The PLC data transmission is just to be called a form to it in a piece of and continuous address that the data of the inner part delivers the other party, we, the PLC of the other party passes to read data in the watch to carry on the operation. If the data that data in the watch is a to establish generally, that is just the general data transmission, for example today of oil price rise, I want to deliver the price of the oil price to lose the oil ally on board, that is the share of the data; But take data in the watch for an instruction procedure that controls the PLC, that had the difficulty very much, for example you have to control one pedestal robot to press the action work that you imagine, you will draw up for it the form that a procedure combine with the data sends out to pass by.The form that information transport contain single work, the half a work and the difference of a workses .The meaning of the single work also is to say both, a can send out only, but a can receive only, for example a spy he can receive the designation of the superior only, but can't give the superior reply; A work of half is also 2 and can can send out similar to accept the data, but can't send out and accept at the same time, for example when you make a phonecall is to can't answer the phone, the other party also; But whole pair works is both can send out and accept the data, and can send out and accept at the same time. Be like the Internet is a typical example.The process that information transport also has synchronous and different step cent: The data line and the clock lines are synchronous when synchronous meaning lie in sending out the data, is also the data signal and the clock signals to be carry on by the CPU to send out at the same time, this needs to all want the specialized clock signal each other to carry on the transmission and connect to send, and is constrained, the characteristics of this kind of method lies in its speed very quick, but correspond work time of take up the CPU and also want to be long oppositely, at the same time the technique difficulty also very big. Its request lies in can'ting have an error margins in a datas deliver, otherwise the whole piece according to compare the occurrence mistake, this on the hardware is a bigger difficulty. Applied more and more extensive in some appropriative equipmentses, be like the appropriative medical treatment equipments, the numerical signal equipments...etc., in compare the one data deliver, its result is very good.And the different step is an application the most extensive, this receive benefit in it of technique difficulty is opposite and want to be small, at the same time not need to prepare the specialized clock signal, its characteristics to lie in, its data is partition, the long-lost send out and accept, be the CPU is too busy of time can grind to a stop sex to work, also reduced the difficulty on the hardware, the data throw to lose at the same time opposite want to be little, we can pass the examination of the data to observe whether the data that we send out has the mistake or not, be like strange accidentally the method, tired addition and eight efficacies method etc., can use to helps whether the data that we examine to send out have or not the mistake occurrence, pass the feedback to carry on the discriminator.A line of transmission of the information contain a string of and combine the cent of: The usual PLC is 8 machines, certainly also having 16 machines. We can be an at the time of sending out the data a send out to the other party, also can be 88 send out the data to the other party, an and 8 differentiationses are also the as that we say to send out the data and combine sends out the data. A speed is more and slowly, but as long as 2 or three lines can solve problem, and can use the telephone line to carry on the long range control. But combine the oscular transmission speed is very quick of, it is a string of oscular of 25600%, occupy the advantage in the short distance, the in view of the fact TTL electricity is even, being limited by the scope of one meter generally, it combine unwell used for the data transmission of the long pull, thus the cost is too expensive.Under a lot of circumstances we are total to like to adopt the string to combine the conversion chip to carry on deliver, under this kind of circumstance not need us to carry on to depositted the machine to establish too and complicatedly, but carry on the data exchanges through the data transmission instruction directly, but is not a very viable way in the correspondence, because the PLC of the other party must has been wait for your data exportation at the time of sending out the data, it can't do other works.When you are reading the book, you hear someone knock on door, you stop to start up of affair, open the door and combine to continue with the one who knock on door a dialogue, the telephone of this time rang, you signal hint to connect a telephone, after connecting the telephone through, return overdo come together knock on door to have a conversation, after dialogue complete, you continue again to see your book, this kind of circumstance we are called the interruption to it, it has the authority, also having sex of have the initiative, the PLC had such function .Its characteristics lie in us and may meet the urgently abrupt affairs in the operation process of the equipments, we want to stop to start immediately up of work, the whereabouts manages the more important affair, this kind of circumstance is we usually meet of, PLC while carry out urgent mission, total will keep the current appearance first, for example the address of the procedure, CPU of tired add the machine data etc., be like to to stick down which the book that we see is when we open the door the page or simply make a mark, because we treat and would still need to continue immediately after book of see the behind. The CPU always does the affair that should do according to our will, but your mistake of give it an affair, it also would be same to do, this we must notice.The interruption is not only a, sometimes existing jointly with the hour several inside break, break off to have the preferred Class, they will carry out the interruption of the higher Class according to person's request. This kind of breaks off the medium interruption to also became to break off the set. The Class that certainly break off is relevant according to various resources of CPU with internal PLC, also following a heap of capacity size of also relevant fasten.The contents that break off has a lot of kinds, for example the exterior break off, correspondence in of send out and accept the interruption and settle and the clock that count break off, still have the WDT to reset the interruption etc., they enriched the CPU to respond to the category while handle various business. Speak thus perhaps you can't comprehend the internal structure and operation orders of the interruption completely also, we do a very small example to explain.Each equipments always will not forget a button, it also is at we meet the urgent circumstance use of, that is nasty to stop the button. When we meet the Human body trouble and surprised circumstances we as long as press it, the machine stops all operations immediately, and wait for processing the over surprised empress recover the operation again.Nasty stop the internal I/ O of the internal CPU of the button conjunction PLC to connect up, be to press button an exterior to trigger signal for CPU, the CPU carries on to the I/ O to examine again, being to confirm to have the exterior to trigger the signal, CPU protection the spot breaks off procedure counts the machine turn the homologous exterior I/ O automatically in the procedure to go to also, be exterior interruption procedure processing complete, the procedure counts the machine to return the main procedure to continue to work.Have 1:00 can what to explain is we generally would nasty stop the button of exterior break off to rise to the tallest Class, thus guarantee the safety.When we are work a work piece, giving the PLC a signal, counting PLC inner part the machine add 1 to compute us for a day of workload, a count the machine and can solve problem in brief, certainly they also can keep the data under the condition of dropping the electricity, urging the data not to throw to lose, this is also what we hope earnestly.The PLC still has the function that the high class counts the machine, being us while accept some datas of high speed, the high speed that here say is the data of the in all aspects tiny second class, for example the bar code scanner is scanning the data continuously, calculating high-speed signal of the data processor DSP etc., we will adopt the high class to count the machine to help we carry on count. It at the PLC carries out the procedure once discover that the high class counts the machine to should of interruption, will let go of the work on the hand immediately. The trapezoid diagram procedure that passes by to weave the distance again explains the high class for us to carry out procedure to count machine would automatic performance to should of work, thus rise the Class that the high class counts the machine to high one Class.You heard too many this phrases perhaps:" crash", the meaning that is mostly is a workload of CPU to lead greatly, the internal resources shortage etc. the circumstance can't result in procedure circulate. The PLC also has the similar circumstance, there is a watchdog WDT in the inner part of PLC, we can establish time that a procedure of WDT circulate, being to appear the procedure to jump to turn the mistake in the procedure movement process or the procedure is busy, movement time of the procedure exceeds WDT constitution time, the CPU turn but the WDT reset the appearance. The procedure restarts the movement, but will not carry on the breakage to the interruption.The PLC development has already entered for network ages of correspondence from the mode of the one, and together other works control the net plank and I/ O card planks to carry on the share easily. A state software can pass all se hardwares link, more animation picture of keep the view to carries on the control, and cans pass the Internet to carry on the control in the foreign land, the blast-off that is like the absolute being boat No.5 is to adopt this kind of way to make airship go up the sky.The development of the higher layer needs our continuous effort to obtain.The PLC emergence has already affected a few persons fully, we also obtained more knowledge and precepts from the top one experience of the generation, coming to the continuous development PLC technique, push it toward higher wave tide.中文翻译:可编程控制器技术讨论与未来发展随着时代的发展,当今的技术也日趋完善、竞争愈演愈烈，单靠人工的操作已不能满足于目前的制造业前景，也无法保证更高质量的要求和高新技术企业的形象。

中英文文献翻译-关于PLC外文翻译

外文文献PLC technique discussion and future developmentProgrammable Controller (Programmable Logic Controller, customarily referred to as PLC) is a microprocessor as the core of the general industrial automation devices. Is in the late 1960 s in the relay control system developed on the basis of, it will traditional relay control technology combined with computer technology and communication technology, has a simple structure, superior performance, high reliability, flexible, general and convenient use, easy to programming. In particular, the characteristics of the PLC is shown as the followingAspects: (1) the high reliability of hardware. PLC is specialized in industrial environment under the conditions of application and design. Can be placed in a well designed PLC has a very high voltage noise, electromagnetic interference and mechanical vibration, extreme temperature, and humidity environment. Is in the aspect of hardware design, first of all with high quality components, and adopt reasonable system structure, strengthening, simplify installation, makes it easy to anti vibration shock, to the printed circuit board design, machining and welding process are taken very strict measures, and on the circuit, the structure and process had taken some unique ways. Because the PLC itself has very high reliability, so in the event of a failure parts mostly focused on the input/output parts and such as sensors, limit switches, photoelectric switch, electromagnetic valve, motor, etc. programming and easy to use. Automatic control by microcomputer, commonly used assembly language programming, difficult to grasp, requires the user has a certain level of knowledge of computer hardware and software. PLC used for process control, problem oriented programming method, compared with the currently used assembly language microcomputer control, while inside the PLC increases the interpretation procedure, to increase the program's execution time, but for most of the mechanical and electrical control equipment, this loss is negligible. (3) Wiring is simple, high universality. In the case of electrical matching, PLC connection just put the input signal of the device (button, switch, etc.) connected to the input terminal of PLC, will accept the output signal of executive control tasks (contactor, solenoid valves), executive components connected to the PLC output terminals. Wiring is simple, leaves out the conventional relay control system wiring and removing the trouble. PLC programming logic provides can change according to the requirements of logical relationship, so that production line automation process can change at will. This performance makes the PLC has the very high economic benefits. Used to connect field devices of the hardware interface design has actually become a part of PLC, since the diagnosis of modular interface circuit can point to the fault, and easy to troubleshooting and replacement of fault parts, so that the software and hardware design of the site electrical personnel and technical personnel to use. (4) can be connected tocontrol network system. PLC can be connected to become powerful network system. General PLC network can be divided into two kinds: one kind is a low-speed network, USES the master-slave mode communication, transfer rate from the potter thousands and thousands of potter to the transmission distance is 500 ~ 2500 m; Another kind of high-speed network, USES the token passing mode communication, communication rate of 1 m to 10 MBPS, transmission distance is 500 ~ 1000 m, 1024 online nodes. These two types of networks are linked together, can be compatible with different types of programmable controller and computer, forming control range a lot of local network. 5. Easy to install, easy to maintain. PLC installation is simple and powerful functions, its relatively small size allows them to install the relay control box usually required for half of the space. In the large PLC system installation, remote I/o in the optimal location. Remote I/O station through double axis of coaxial cable, or even to the CPU, which greatly reduces the material and labor, remote subsystem method means from different parts of the system can be installed in field. Because almost all of the components are modular, only need to change when maintaining module level plug-in components, fault detection circuit diagnosis indicator will be embedded in each part, can indicate the device is working correctly, the resistance in programming is visible input/output devices ON or OFF, still can write programming instructions to report failures. In addition, PLC automation technology, computer technology and communication technology together, and you can also complete the following functions: logic control, timing control, counting control, stepper control, A/D and D/A conversion, data processing, communication network and monitoring on the control system. In general, the application of PLC have boom in the world, the PLC development direction mainly toward miniaturization, deflationary force, standardization, standardization, intelligence, high speed, large capacity, network development, this will make the PLC function is stronger, higher reliability, more convenient use, wide application and moreThe PLC biggest characteristics lie in: The electrical engineering teacher already no longer electric hardware up too many calculations of cost, as long as order the importation that the button switch or the importation of the sensors order to link the PLC up can solve problem, pass to output to order the conjunction contact machine or control the start equipments of the big power after the electric appliances, but the exportation equipments direct conjunction of the small power can.PLC internal containment have the CPU of the CPU, and take to have an I/ O for expand of exterior to connect a people's address and saving machine three big pieces to constitute, CPU core is from an or many is tired to add the machine to constitute, mathematics that they have the logic operation ability, and can read the procedure save the contents of the machine to drive the homologous saving machine and I/ Os to connect after pass the calculation; The I/ O add inner part is tired the input and output system of the machine and exterior link, and deposit the related data into the procedure saving machine or data saving machine; The saving machine can deposit the data that the I/ O input in the saving machine, and in work adjusting to become tired to add themachine and I/ Os to connect, saving machine separately saving machine RAM of the procedure saving machine ROM and dates, the ROM can do deposit of the data permanence in the saving machine, but RAM only for the CPU computes the temporary calculation usage of hour of buffer space.The PLC anti- interference is very and excellent, our root need not concern its service life and the work situation bad, these all problems have already no longer become the topic that we fail, but stay to our is a concern to come to internal resources of make use of the PLC to strengthen the control ability of the equipments for us, make our equipments more gentle.PLC language is not we imagine of edit collected materials the language or language of Cs to carry on weaving the distance, but the trapezoid diagram that the adoption is original after the electric appliances to control, make the electrical engineering teacher while weaving to write the procedure very easy comprehended the PLC language, and a lot of non- electricity professional also very quickly know and go deep into to the PLC.Is PLC one of the advantage above and only, this is also one part that the people comprehend more and easily, in a lot of equipments, the people have already no longer hoped to see too many control buttons, they damage not only and easily and produce the artificial error easiest, small is not a main error perhaps you can still accept; But lead even is a fatal error greatly is what we can't is tolerant of. New technique always for bringing more safe and convenient operation for us, make we a lot of problems for face on sweep but light, do you understand the HMI? Says the HMI here you basically not clear what it is, also have no interest understanding, change one inside text explains it into the touch to hold or man-machine interface you knew, and it combines with the PLC to our larger space.HMI the control not only is reduced the control press button, increase the vivid of the control, more main of it is can sequence of, and at can the change data input to output the feedback with data, control in the temperature curve of imitate but also can keep the manifestation of view to come out. And can write the function help procedure through a plait to provide the help of various what lies in one's power, the one who make operate reduces the otiose error. Currently the HMI factory is also more and more, the function is also more and more strong, the price is also more and more low, and the noodles of the usage are wide more and more. The HMI foreground can say that think ° to be good very.At a lot of situations, the list is a smooth movement that can't guarantee the equipments by the control of the single machine, but pass the information exchanges of the equipments and equipments to attain the result that we want. For example fore pack and the examination of the empress work preface, we will arrive wrapping information feedback to examine the place, and examine the information of the place to also want the feedback to packing. Pass the information share thus to make both the chain connect, becoming a total body, the match of your that thus make is more close, at each other attain to reflect the result that mutually flick.The PLC correspondence has already come more body now its value, at the PLC and correspondence between PLC, can pass the communication of the information and the share of the dates to guarantee that of the equipments moderates mutually, the result that arrive already to repair with each other. Data conversion the adoption RS232 between PLC connect to come to the transmission data, but the RS232 pick up a people and can guarantee 10 meters only of deliver the distance, if in the distance of 1000 meters we can pass the RS485 to carry on the correspondence, the longer distance can pass the MODEL only to carry on deliver.The PLC data transmission is just to be called a form to it in a piece of and continuous address that the data of the inner part delivers the other party, we, the PLC of the other party passes to read data in the watch to carry on the operation. If the data that data in the watch is a to establish generally, that is just the general data transmission, for example today of oil price rise, I want to deliver the price of the oil price to lose the oil ally on board, that is the share of the data; But take data in the watch for an instruction procedure that controls the PLC, that had the difficulty very much, for example you have to control one pedestal robot to press the action work that you imagine, you will draw up for it the form that a procedure combine with the data sends out to pass by.The form that information transport contain single work, the half a work and the difference of a workers .The meaning of the single work also is to say both, a can send out only, but a can receive only, for example a spy he can receive the designation of the superior only, but can't give the superior reply; A work of half is also 2 and can send out similar to accept the data, but can't send out and accept at the same time, for example when you make a phone call is to can't answer the phone, the other party also; But whole pair works is both can send out and accept the data, and can send out and accept at the same time. Be like the Internet is a typical example.The process that information transport also has synchronous and different step cent: The data line and the clock lines are synchronous when synchronous meaning lie in sending out the data, is also the data signal and the clock signals to be carry on by the CPU to send out at the same time, this needs to all want the specialized clock signal each other to carry on the transmission and connect to send, and is constrained, the characteristics of this kind of method lies in its speed very quick, but correspond work time of take up the CPU and also want to be long oppositely, at the same time the technique difficulty also very big. Its request lies in canting have an error margins in a dates deliver, otherwise the whole piece according to compare the occurrence mistake, this on the hardware is a bigger difficulty. Applied more and more extensive in some appropriative equipments, be like the appropriative medical treatment equipments, the numerical signal equipments...etc., in compare the one data deliver, its result is very good.And the different step is an application the most extensive, this receive benefit in it of technique difficulty is opposite and want to be small, at the same time not need to prepare the specialized clock signal, its characteristics to lie in, its data is partition, the long-lost send out andaccept, be the CPU is too busy of time can grind to a stop sex to work, also reduced the difficulty on the hardware, the data throw to lose at the same time opposite want to be little, we can pass the examination of the data to observe whether the data that we send out has the mistake or not, be like strange accidentally the method, tired addition and eight efficacies method etc., can use to helps whether the data that we examine to send out have or not the mistake occurrence, pass the feedback to carry on the discriminator.A line of transmission of the information contains a string of and combine the cent of: The usual PLC is 8 machines, certainly also having 16 machines. We can be an at the time of sending out the data a send out to the other party, also can be 88 send out the data to the other party, an and 8 differentiations are also the as that we say to send out the data and combine sends out the data. A speed is more and slowly, but as long as 2 or three lines can solve problem, and can use the telephone line to carry on the long range control. But combine the ocular transmission speed is very quick of, it is a string of ocular of 25600%, occupy the advantage in the short distance, the in view of the fact TTL electricity is even, being limited by the scope of one meter generally, it combine unwell used for the data transmission of the long pull, thus the cost is too expensive.Under a lot of circumstances we are total to like to adopt the string to combine the conversion chip to carry on deliver, under this kind of circumstance not need us to carry on to deposited the machine to establish too and complicatedly, but carry on the data exchanges through the data transmission instruction directly, but is not a very viable way in the correspondence, because the PLC of the other party must has been wait for your data exportation at the time of sending out the data, it can't do other works.When you are reading the book, you hear someone knock on door, you stop to start up of affair, open the door and combine to continue with the one who knock on door a dialogue, the telephone of this time rang, you signal hint to connect a telephone, after connecting the telephone through, return overdo come together knock on door to have a conversation, after dialogue complete, you continue again to see your book, this kind of circumstance we are called the interruption to it, it has the authority, also having sex of have the initiative, the PLC had such function .Its characteristics lie in us and may meet the urgently abrupt affairs in the operation process of the equipments, we want to stop to start immediately up of work, the whereabouts manages the more important affair, this kind of circumstance is we usually meet of, PLC while carry out urgent mission, total will keep the current appearance first, for example the address of the procedure, CPU of tired add the machine data etc., be like to stick down which the book that we see is when we open the door the page or simply make a mark, because we treat and would still need to continue immediately after book of see the behind. The CPU always does the affair that should do according to our will, but your mistake of give it an affair, it also would be same to do, this we must notice.The interruption is not only a, sometimes existing jointly with the hour several inside break,break off to have the preferred Class, they will carry out the interruption of the higher Class according to person's request. This kind of breaks off the medium interruption to also became to break off the set. The Class that certainly break off is relevant according to various resources of CPU with internal PLC, also following a heap of capacity size of also relevant fasten.The contents that break off has a lot of kinds, for example the exterior break off, correspondence in of send out and accept the interruption and settle and the clock that count break off, still have the WDT to reset the interruption etc., they enriched the CPU to respond to the category while handle various business. Speak thus perhaps you can't comprehend the internal structure and operation orders of the interruption completely also, we do a very small example to explain.Each equipment always will not forget a button, it also is at we meet the urgent circumstance use of, which is nasty to stop the button. When we meet the Human body trouble and surprised circumstances we as long as press it, the machine stops all operations immediately, and wait for processing the over surprised empress recover the operation again. Nasty stop the internal I/ O of the internal CPU of the button conjunction PLC to connect up, be to press button an exterior to trigger signal for CPU, the CPU carries on to the I/ O to examine again, being to confirm to have the exterior to trigger the signal, CPU protection the spot breaks off procedure counts the machine turn the homologous exterior I/ O automatically in the procedure to go to also, be exterior interruption procedure processing complete, the procedure counts the machine to return the main procedure to continue to work. Have 1:00 can what to explain is we generally would nasty stop the button of exterior break off to rise to the tallest Class, thus guarantee the safety.When we are work a work piece, giving the PLC a signal, counting PLC inner part the machine add 1 to compute us for a day of workload, a count the machine and can solve problem in brief, certainly they also can keep the data under the condition of dropping the electricity, urging the data not to throw to lose, this is also what we hope earnestly.The PLC still has the function that the high class counts the machine, being us while accept some dates of high speed, the high speed that here say is the data of the in all aspects tiny second class, for example the bar code scanner is scanning the data continuously, calculating high-speed signal of the data processor DSP etc., we will adopt the high class to count the machine to help we carry on count. It at the PLC carries out the procedure once discover that the high class counts the machine to should of interruption, will let go of the work on the hand immediately. The trapezoid diagram procedure that passes by to weave the distance again explains the high class for us to carry out procedure to count machine would automatic performance to should of work, thus rise the Class that the high class counts the machine to high one Class.You heard too many this phrases perhaps:" crash", the meaning that is mostly is a workload of CPU to lead greatly, the internal resources shortage etc. the circumstance can't result in procedure circulate. The PLC also has the similar circumstance, there is a watchdog WDT in theinner part of PLC, we can establish time that a procedure of WDT circulate, being to appear the procedure to jump to turn the mistake in the procedure movement process or the procedure is busy, movement time of the procedure exceeds WDT constitution time, the CPU turn but the WDT reset the appearance. The procedure restarts the movement, but will not carry on the breakage to the interruption.The PLC development has already entered for network ages of correspondence from the mode of the one, and together other works control the net plank and I/ O card planks to carry on the share easily. A state software can pass all se hardwires link, more animation picture of keep the view to carries on the control, and cans pass the Internet to carry on the control in the foreign land, the blast-off that is like the absolute being boat No.5 is to adopt this kind of way to make airship go up the sky.The development of the higher layer needs our continuous effort to obtain. The PLC emergence has already affected a few persons fully, we also obtained more knowledge and precepts from the top one experience of the generation, coming to the continuous development PLC technique, push it toward higher wave tide.Knowing the available PLC network options and their best applications will ensure an efficient and flexible control system design.The programmable logic controller's (PLC) ability to support a range of communication methods makes it an ideal control and data acquisition device for a wide variety of industrial automation and facility control applications. However, there is some confusion because so many possibilities exist. To help eliminate this confusion, let's list what communications are available and when they would be best applied.To understand the PLC communications versatility, let's first define the terms used in describing the various systems.ASCII: This stands for "American Standard Code for Information Interchange." As shown in Fig. 1, when the letter "A" is transmitted, for instance, it's automatically coded as "65" by the sending equipment. The receiving equipment translates the "65" back to the letter "A." Thus, different devices can communicate with each other as long as both use ASCII code.ASCII module: This intelligent PLC module is used for connecting PLC to other devices also capable of communicating using ASCII code as a vehicle.Bus topology: This is a linear local area network (LAN) arrangement, as shown in Fig. 2A, in which individual nodes are tapped into a main communications cable at a single point and broadcast messages. These messages travel in both directions on the bus from the point of connection until they are dissipated by terminators at each end of the bus.CPU: This stands for "central processing unit," which actually is that part of a computer, PLC, or other intelligent device where arithmetic and logical operations are performed and instructions are decoded and executed.Daisy chain: This is a description of the connection of individual devices in a PLC network, where, as shown in Fig. 3, each device is connected to the next and communications signals pass from one unit to the next in a sequential fashion.Distributed control: This is an automation concept in which portions of an automated system are controlled by separate controllers, which are located in close proximity to their area of direct control (control is decentralized and spread out over the system).Host computer: This is a computer that's used to transfer data to, or receive data from, a PLC in a PLC/computer network.Intelligent device: This term describes any device equipped with its own CPU.I/O: This stands for "inputs and outputs," which are modules that handle data to the PLC (inputs) or signals from the PLC (outputs) to an external device.Kbps: This stands for "thousand bits per second," which is a rate of measure for electronic data transfer.Mbps: This stands for "million bits per second."Node: This term is applied to any one of the positions or stations in a network. Each node incorporates a device that can communicate with all other devices on the network.Protocol: The definition of how data is arranged and coded for transmission on a network.Ring topology. This is a LAN arrangement, as shown in Fig. 2C, in which each node is connected to two other nodes, resulting in a continuous, closed, circular path or loop for messages to circulate, usually in one direction. Some ring topologies have a special "loop back" feature that allows them to continue functioning even if the main cable is severed.RS232. This is an IEEE standard for serial communications that describes specific wiring connections, voltage levels, and other operating parameters for electronic data communications. There also are several other RS standards defined.Serial: This is an electronic data transfer scheme in which information is transmitted one bit at a time.Serial port: This the communications access point on a device that is set up for serial communications.Star topology. This is a LAN arrangement in which, as shown in Fig. 2B, nodes are connected to one another through a central hub, which can be active or passive. An active hub performs network duties such as message routing and maintenance. A passive central hub simply passes the message along to all the nodes connected to it.Topology: This relates to a specific arrangement of nodes in a LAN in relation to one another.Transparent: This term describes automatic events or processes built into a system that require no special programming or prompting from an operator.Now that we're familiar with these terms, let's see how they are used in describing the available PLC network options.PLC network optionsPLC networks provide you with a variety of networking options to meet specific control and communications requirements. Typical options include remote I/O, peer-to-peer, and host computer communications, as well as LANs. These networks can provide reliable and cost-effective communications between as few as two or as many as several hundred PLC, computers, and other intelligent devices.Many PLC vendors offer proprietary networking systems that are unique and will not communicate with another make of PLC. This is because of the different communications protocols, command sequences, error-checking schemes, and communications media used by each manufacturer.However, it is possible to make different PLC "talk" to one another; what's required is an ASCII interface for the connection(s), along with considerable work with software.Remote I/0 systemsA remote I/O configuration, as shown in Fig. 4A, has the actual inputs and outputs at some distance from the controller and CPU. This type of system, which can be described as a "master-and-slave" configuration, allows many distant digital and analog points to be controlled by a single PLC. Typically, remote I/Os are connected to the CPU via twisted pair or fiber optic cables.Remote I/O configurations can be extremely cost-effective control solutions where only a few I/O points are needed in widely separated areas. In this situation, it's not always necessary, or practical for that matter, to have a controller at each site. Nor is it practical to individually hard wire each I/O point over long distances back to the CPU. For example, remote I/O systems can be used in acquiring data from remote plant or facility locations. Information such as cycle times, counts, duration or events, etc. then can be sent back to the PLC for maintenance and management reporting.In a remote I/O configuration, the master controller polls the slaved I/O for its current I/O status. The remote I/O system responds, and the master PLC then signals the remote I/O to change the state of outputs as dictated by the control program in the PLC memory. This entire cycle occurs hundreds of times per second.Peer-to-peer networksPeer-to-peer networks, as shown in Fig. 4B, enhance reliability by decentralizing the control functions without sacrificing coordinated control. In this type of network, numerous PLC are connected to one another in a daisy-chain fashion, and a common memory table is duplicated in the memory of each. In this way, when any PLC writes data to this memory area, the information is automatically transferred to all other PLCs in the network. They then can use this information in their own operating programs.With peer-to-peer networks, each PLC in the network is responsible for its own control site。

PLC基础知识简介外文文献翻译、中英文翻译、外文翻译

附录：外文资料译文PLC elementary knowledge synopsisIn the automated control domain, PLC is one kind of important control device. At present, in the world has more than 200 factories to produce more than 300 varieties PLC product, applies in the automobile (23%), the grain processing (16.4%), chemistry/drugs manufacture (14.6%), the metal/mine (11.5%), the paper pulp/papermaking (11.3%) and so on the profession. In order to make fellow beginners conveniently to understand PLC, this article to the PLC development, the basic structure, the disposition, using and so on the elementary knowledge makes a synopsis.First, PLC development courseIn the industrial production process, the massive switches quantity sequential control, it carries on the smooth movement according to the logical condition, and defers to the logical relations to carry on the chain-like protection movement the control, and massive data acquisition. In the tradition, these functions are realize through air operated or the electricity control system. In 1968 American GM (general automobile) the company proposed the substitution continues the electricity control device the request, the second year, the American numeral company developed based on the integrated circuit and the electronic technology control device, used sequenced the method to apply for the first time to the electrical control, this was the first generation of programmable foreword controller, calledProgrammable Controller (PC).After the personal computer (is called PC) to develop, in order to be convenient, also in order to reflect the programmable controller the function characteristic, the programmable foreword controller chooses a name is Programmable Logic Controller (PLC), now, still frequently was called PLC PC.The PLC definition has many kinds. The international electrician committee (IEC) to PLC the definition is: The programmable controller is one kind of digital operation operation electronic system, specially for applies under the industry environment designs. It uses the programmable foreword the memory, uses for to carry out the logic operation, the sequential control in its internal storage, fixed time, counts with operation the and so on arithmetic operation instruction, and through digital, the simulation input and the output, controls each kind of type the machinery or the production process. The programmable foreword controller and its the related equipment, all should according to easy form a whole with the industry control system, is easy to expand its function the principle design.On the century 80's to the 90's intermediate stages, are PLC develop the quickest time, the yearly rate continuously maintenance are 30-40%. In this time, PLC in the processing simulation quantity ability, the digital operation ability, the man-machine connection ability and the networking capability obtains the large scale enhancement, PLC gradually enters the process control domain, substituted in certain applications has been at the dominant position in the process control domain the DCS system.PLC has the versatility strongly, the easy to operate,the adaption surface broad, the reliability high, the antijamming ability strong, the programming is simple and so on the characteristic. PLC in the industrial automation control specially is in the sequential control status, in future which may foresee, is unable to substitute.Second, PLC constitutionFrom the structure the minute, PLC divides into the stationary type and the combined type (module type) two kinds. Stationary PLC including the CPU board, the I/O board, demonstrated the kneading board, the memory block, the power source and so on, these element groups synthesize a not dismantable whole. Module type PLC including the CPU module, the I/O module, the memory, the power source module, the ledger wall or the rack, these modules may defer to the certain rule combination disposition. Second, PLC constitution.Third, CPU constitutionCPU is the PLC core, plays nerve center's role, every time wraps PLC at least to have CPU, it function receive and storage user program and data which entrusts with according to the PLC system program, with scanning way gathering the condition or the data which sends by the scene input device, and stores the stipulation in the register, simultaneously, diagnoses the power source and in the PLC internal circuit active status and the programming process grammatical error and so on. After enters the movement, reads from the user program memory by the strip takes the instruction, the duty which stipulated according to the instruction produces the corresponding control signal again after the analysis, directs the related control circuit.CPU mainly by the logic unit, the controller, theregister and realizes the data, the control and the condition main line constitution which between them relates, the CPU unit also includes the periphery chip, the main line connection and the related electric circuit. The memory mainly uses in the stored routine and the data, is the PLC essential composition unit.Looked like in the user, nonessential multianalysis CPU internal circuit, but or should have the enough understanding to each part of work mechanism. The CPU controller controls the CPU work, reads by it takes the instruction, the interpretive order and carries out the instruction. But the work rhythm by shakes the signal control. The logic unit uses in to carry on the numeral or the logic operation, works under the controller direction. The register participation operation, coexists stores the operation the intermediate result, it also is works under the controller direction.The CPU speed and the memory capacity are the PLC important parameter, they are deciding the PLC working speed, the IO quantity and the software capacity and so on, therefore is limiting the control scale.Fourth, I/O modulePLC and the electrical return route connection, is (I/O) completes through the input output unit. The I/O module integrated the PLC I/O electric circuit, its input temporary storage device reflection input signal condition, output point reflection output latch condition. The load module transforms the electrical signal the digital signal to enter the PLC system, the output module is opposite. I/O divides into the switch quantity input (DI), switch quantity output (DO), simulation quantity input (AI), simulation quantity output (AO) and so on module.The switch quantity is refers has and closes (or 1 and 0) two kind of conditions signals, the simulation quantity is only a quantity which refers continuously changes. Commonly used I/O classifies as follows:Switch quantity: Divides equally according to the voltage water, has 220VAC, 110VAC, 24VDC, divides according to the isolation way, has the relay isolation and the transistor isolation.Simulation quantity: Divides according to the signal type, has the electric current (4-20mA,0-20mA), the voltage (0-10V,0-5V, -10-10V) and so on, divides according to the precision, has 12bit,14bit,16bit and so on.Besides above general I/O, but also has the special I/O module, like module and so on thermal resistance, thermo-element, pulse.According to the I/O points determination module specification and the quantity, the I/O module may be many may be few, but its biggest number the basic disposition ability which can manage CPU, namely biggest ledger wall or rack Key slot number limit.Fifth, power source moduleThe PLC power source uses in is the PLC various modules integrated circuit provides the work power source. At the same time, some also provides 24V for the input circuit the work power source. The mains input type includes: (What the alternating current supply (220VAC or 110VAC), the direct-current power supply is commonly used is 24VAC).Sixth, PLC system other equipment1st, programs the equipment: The programming is the PLC development application, the monitor movement, the inspection maintains the essential component, uses in toprogram, makes some hypotheses to the system, monitors the system working condition which PLC and PLC controls, but it not directly participates in the scene control movement. Small programming PLC generally has the grasping programming, at present generally (movement programming software) acts as the programming by the computer.2nd, man-machine contact surface: The simplest man-machine contact surface is the indicating lamp and the button, at present the liquid crystal screen (or touches screen) a formula writing style operator terminal application to be more and more widespread, (movement configuration software) acts as the man-machine contact surface by the computer extremely to popularize.3rd, input-output device: Uses in permanently the memory user data, like EPROM, EEPROM reading in, bar code microreader, input simulation quantity potentiometer, printer and so on.PLC基础知识简介在自动化控制领域，PLC是一种重要的控制设备。

PLC中英文资料外文翻译

可编程控制器技术讨论与未来发展学生姓名： ******所在院系： ******所学专业： ******导师姓名： ******完成时间：******外文资料PLCtechnique discussion and future developmentWith the development of the times, today's technology is maturing, competition intensified。

rely on manual operation does not satisfy the current industry outlook, there is no guarantee of higher quality requirements and high-tech corporate image.People saw in the production practice, automation to bring great convenience and product quality assurance, but also reduce the labor intensity, reducing the staff on the establishment in many complex production process is difficult to achieve target control, the overall optimization, optimal decision-making, skilled operatives, technicians or specialists, managers can easily determine and operate it, you can get satisfactory results. artificial intelligence research is the use of computers to achieve the target, the analog These intelligent behavior, through coordination of the human brain and a computer to combine human models for solving very complex problem of finding the best way.PLC's most important feature is: electrical engineer electrical hardware no longer spend too much scheming, as long as the button switch or sensor input connected to the PLC input point will solve the problem by connecting the output point contacts or relay to control the power of the boot device, and small power output devices can be connected directly.Contained within the PLC having a central processor of the CPU, and with an external I / O port expansion I / O interface and the memory addresses of three major components, CPU core is formed by one or more accumulators, which have the logical math capabilities, and can read the contents of the program memory to drive through the calculation of the corresponding memory and I / O interface。

PLC控制系统外文文献翻译、中英文翻译、外文翻译

PLC控制系统一、PLC概述可编程控制器是60年代末在美国首先出现的，当时叫可编程逻辑控制器PLC （Programmable Logic Controller），目的是用来取代继电器。

以执行逻辑判断、计时、计数等顺序控制功能。

提出PLC概念的是美国通用汽车公司。

PLC的基本设计思想是把计算机功能完善、灵活、通用等优点和继电器控制系统的简单易懂、操作方便、价格便宜等优点结合起来，控制器的硬件是标准的、通用的。

根据实际应用对象，将控制内容编成软件写入控制器的用户程序存储器内,使控制器和被控对象连接方便。

70年代中期以后，PLC已广泛地使用微处理器作为中央处理器，输入输出模块和外围电路也都采用了中、大规模甚至超大规模的集成电路，这时的PLC已不再是仅有逻辑(Logic)判断功能，还同时具有数据处理、PID调节和数据通信功能。

国际电工委员会(IEC)颁布的可编程控制器标准草案中对可编程控制器作了如下的定义：可编程控制器是一种数字运算操作的电子系统，专为在工业环境下应用而设计。

它采用了可编程序的存储器，用来在其内部存储执行逻辑运算，顺序控制、定时、计数和算术运算等操作的指令，并通过数字式和模拟式的输入和输出，控制各种类型的机械或生产过程。

可编程控制器及其有关外围设备，易于与工业控制系统联成一个整体，易于扩充其功能的设计。

可编程控制器对用户来说，是一种无触点设备，改变程序即可改变生产工艺。

目前，可编程控制器已成为工厂自动化的强有力工具，得到了广泛的普及推广应用。

可编程控制器是面向用户的专用工业控制计算机，具有许多明显的特点。

①可靠性高，抗干扰能力强；②编程直观、简单；③适应性好；④功能完善，接口功能强二、PLC的历史1968年，Richard E. Morley创造出了新一代工业控制装置可编程逻辑控制器(PLC),现在，PLC已经被广泛应用于工业领域，包括机械制造也、运输系统、化学过程设备、等许多其他领域。

PLC及变频器技术中英文对照外文翻译文献

(文档含英文原文和中文翻译)中英文资料对照外文翻译PLC and inverter technology trends1. The development trend of the programmable controller“PLC is one kind specially for the digital operation operation electronic installation which applies under the industry environment designs. It uses may the coding memory, uses for in its internal memory operation and so on actuating logic operation, sequence operation, time, counting and arithmetic operation instructions, and can through digital or the simulation-like input and the output, controls each type the machinery or the production process. PLC and the related auxiliary equipment should according to form a whole easy with the industrial control system, easy to expand its function the principle to design.”In the 21st century, PLC will have a bigger development. Technologically speaking, computer technology's new achievement more will apply in the programmable controller's design and the manufacture, will have the operating speed to be quicker, the storage capacity to be bigger, an intelligent stronger variety to appear; Looked from the product scale that further develops to subminiature and the ultra-large direction; Looked from the product overcoatability that the product variety will be richer, the specification to be more complete, the perfect man-machine contact surface, the complete communication facility will adapt eachindustrial control situation demand well; Looked from the market that various countries will produce the multi-variety product the situation to break respectively along with the international competition aggravating, will present the minority several brand monopoly international market the aspect, will present the international general programming language; Looking from the network state of play, the programmable controller and other industrial control computer network constitution large-scale control system is the programmable controller technology development direction. Present computer collection and distribution control system DCS (Distributed Control System) had the massive programmable controller application. Is following computer network's development, the programmable controller takes the automation directed net and the international universal network important component, outside industry and industry numerous domain display more and more major function.2. Inverter technology development trendsInverter into the practical phase of more than 1 / 4 century during this period, the frequency converter technology as the basis of power electronics technology and microelectronics technology manager of a leap in the development, as the new power electronic devices and high-performance microprocessor The application of control technologyand the development of increasingly high cost performance of the inverter, more and more small size, but manufacturers are still in constant frequency converter to achieve the further miniaturization and doing new efforts. From a technical point of view, with the frequency converter to further expand the market of the future, with the converter and inverter technology will be on the development of technologies in the following areas further development:(1) large capacity and small size;(2) high-performance and multi-function;(3) enhance the ease-of-use;(4) increase in life expectancy and reliability;(5) of pollution-free.Large capacity and small size of the power semiconductor devices will be with the development of continuous development. In recent years, driven by a voltage power semiconductor devices IGBT (Isolated Gate Bipolar Transistor, isolation gate bipolar transistors) has developed very rapidly and quickly into the traditional use of BJT (bipolar power transistor) and power MOSFET (FET) The various fields. In addition, the IGBT switching device for the IPM (Intelligent Power Module, IPM) and Monolithic Power IC chip will power switching devices and driving circuit,such as the protection of integrated circuits in the same package, with high performance and reliability The merits, with their high current and high pressure of the development of small and medium-sized converter will certainly be more widely used.With micro-electronics technology and semiconductor technology development, for Inverter CPU and semiconductor devices and a variety of sensors of getting higher and higher. With the frequency converter technology and the development of the growing maturity of the exchange governor, modern control theory are constantly new applications. These have further improved the performance of inverter provided the conditions. In addition, with the frequency converter to further promote the use and support are also constantly made new demands, the frequency converter manufacturers to continuously improve the performance and frequency converter functions in Inverter new efforts to meet user And the need for the fierce competition in the market in an invincible position.With the frequency converter market continues to expand, how to further enhance the ease-of-use inverter, so that the technical staff and even ordinary non-technical staff can quickly master the use of frequency converter technology has become manufacturers must consider the issue. Because only easy-to-use products can continue to acquire new customersand further expand the market, so the future of the new converter will be more easy to operate.With the development of semiconductor technology and the development of power electronics technology, the frequency converter used in the various components of the life and reliability are constantly improving, they will make their own life and the frequency converter to further increase reliability.In recent years, people have attached great importance to environmental issues, and thus a "green products" name. Therefore, the inverter, must also consider its impact on the surrounding environment.Promote the use of the frequency converter in the early stages of the noise problem was once a big problem. With the low-noise converter IGBT the emergence of this issue has basically been resolved. However, with the noise problem to solve, people's looks and a converter to the surrounding environment and the impact of other continuously explore new solutions. For example, the use of a diode-voltage converter and PWM inverter circuit converter, the frequency converter itself the high harmonics will bring supply voltage and current distortion, and at the same power to affect the other equipment. However, through the use of the frequency converter Rectifier circuit PWM, we can basically solve the problem. Althoughbecause of price and control technology and other aspects of the reasons for the current PWM converter has not been promoting the inverter, but, with the frequency converter technology development and the people of the importance of environmental issues.PLC及变频器技术的发展趋势1．可编程控制器的发展趋势可编程控制器是一种数字运算操作的电子系统，专为在工业环境下应用而设计。

PLC控制系统英文文献+翻译

Beer filling, Gland machine PLC control system1.IntorductionMalt beer production process is divided into manufacturing, manufacturing wort, before fermentation, after fermentation, filtration sterilization, packaging, and so few procedures. Beer filling, Gland part of a packaging machine processes. The membrane filtration of beer after the pipeline into the rotary Jiugang, then the valve into the bottle of wine, Gland, was bottled beer. Beer filling, Gland machine's efficiency and degree of automation direct impact on the level of beer production. China's beer industry to meet the increasing scale of production and the demand for beer modern high-speed filling machinery filling the requirements of domestic beer manufacturers are actively seeking to transform the unit or the filling of beer production equipment, making it a good use Performance, advanced technology and high production efficiency and operating a safe and secure, low maintenance costs of the modernization of beer filling machine.2. Filling beer, Gland principle and control aircraft partsLiquid filling machine by filling principle can be divided into atmospheric filler,filling machines and vacuum pressure on the filling machine. Beer filling,Gland-filling method used pressure is higher than the atmospheric pressure under the filling, storage of the cylinder pressure than the pressure of the bottle, beer bottle into the liquid on pressure.Technology at home and abroad to achieve the filling line is basically: The Rotary Jiugang the rotating movement, placed in Jiugang slots on the empty bottles through the machinery will be fixed at the upper Jiugang vacuum valve to open, closed Vacuum bottles for good treatment, Bozhuan stem from operating, open the valve of the bottle filling CO2 gases, vacuum convex .Round to open the vacuum valve, the bottle will air mixed with CO2 out of gas, open the valve again, the CO2 gas bottle filling, the filling valve on the pressure valve in the bottle close to back-pressure gas pressure at the open-Jiuye Pingbi into the bottle, through pneumatic or electrical control filling valve to achieve the filling of beer. Today's advanced international beer filling, Gland machine control system mainly by the photoelectric switch position detection part and take the bottles with, Jiugang speed part, dominated by the PLC, touch screen and other components. Filling, Gland of the mechanical structure and PLC programmable control devices, frequency stepless speed regulation, human-computer interface, and other modern means of complete automatic control technology, the combination of a mechanical and electrical integration.3. Controlled part of the programmeMany domestic beer manufacturers are now using the filling, Gland of the control system of uneven degree of automation; button and all the manual switch technology have set up operations in a box on the panel, PLC controller for the majority of Japanese companies or OMRON Mitsubishi's early products, equipment chain of control, less protection settings, plus the beer filling the scene poor environment, humidity, such as contact with the switch contacts serious corrosion, the system's signal detection of the high failure rate, resulting in equipment control system Operation of low reliability, the normal operation of equipment, such asshort-cycle phenomenon.To the actual transformation of the Dandong Yalu River Brewery Co., Ltd. of filling, Gland machine control system as an example, the transformation of methods to clarify the control of such equipment thinking and ideas, according to the scene of the actual process conditions, to prepare the operation of the PLC Procedures. For beer filling, Gland control system of the actual situation and in accordance with the actual process conditions at the scene, re-design of the equipment of the PLC control system. This transformation of the same methods and ideas can be applied to other liquids and the transformation of filling equipment.3.1 system hardware configurationJapan's Mitsubishi Corporation to use the FX2N128MRPLC use the system to replace the original 2-OMRON's C60P PLC, the original system of the PLC is due to old models, and computer on-line communications need to configure special converters, the system need to increase the external I / O input points , The extension of spare parts more difficult to find. FX2N128MRPLC is an integrated 128-point I / O controller of the box, a computing speed, command rich, high-cost performance, on-line programming simple and easy extension of the advantages of the Mitsubishi FX series, features the strongest small controller .(1) by the Mitsubishi 900 series of 970 GOT human-computer touch screen system to replace the original use of the button panel display equipment and monitor the operation of operating parameters. 970GOT HMI for the 16-color high-brightness significantly, through the convergence of connectivity and FX2N128MRPLC directly connected to the CPU, achieving rapid response. Has many maintenance features, such as the list-editing features, ladder monitoring (troubleshooting) function, the systemmonitoring functions to find fault and maintenance of PLC Systems. (2) filling, Gland of the frequency converter in the transformation of no replacement, on-site detection signal means-testing is still used switch, switch for detecting long-term work in the humidity of the great occasions, the choice of capacitive proximity switches, according to PLC I / O terminal of the connection mode, select the type of close PNP switch, the control system of Figure 1.3.2 Systems ProgrammingPLC controller programming focus and the core is around Jiugang the rotation speed control and Jiugang on 60 bottles of detecting the location of the displaced, broken bottles, empty bottles at the location of testing and related displacement filling Such as control valves. The bottles displacement of testing procedures, using a Mitsubishi PLC in the left command.Figure 1 control system structure diagram .Bottles displacement of detection, using the left-PLC command, which commands the whole of one of the core control procedures, the main electrical switch detection and bottles at the bottle simultaneously detect mobile, the main motor to every week, just to the corresponding Jiugang Have a bottle of, PLC unit within the internal correspondence that 60 bottles of the unit for the M500 ~ M559, the number of units by the first letter K is set to K60, with each change in a second letter K is set to K1, M50 Reaction of the empty bottles in the short position, and detect the location of the motor speed to go on the frequency shift in the corresponding unit within the built-in "1" or "0", control valves and the corresponding mixing caps The motor stopped and opened. Continuous detection system in place after the 90 empty bottles, stop stirring caps the motor running, testing the number of bottles in accordance with the user's requirements can be arbitrary.A bottle of detection. Rotary Jiugang through pressure to back pressure with the bottle of liquor in the process of empty bottles in the back-pressure, because the bottle itself may crack and other reasons leading to a sudden burst bottles, which need to detect the location of unexploded bottle bottle, in this bottle - The position opened purge solenoid valves, compressed air out, broken bottles at the bottle-blowing from the position in a row after the purge and several bottles of the electromagnetic valve open jet, a high-pressure spray Shuizhu, in the break Bottle position around a few bottles of spray bottles in a row. Detection of broken bottles and bottle-detection switch simultaneously detect movement of breaking bottles, to the main motor of each week, precisely corresponding Jiugang passed a bottle of, PLC unit within the internal correspondence that 20 broken bottles at the unit for the M600 ~ M619, unit With the number of the first letter K is set to K20, with each change in a second letter K is set to K1, M52 response to the location of the broken bottles and detected the location of the motor speed to the frequency shift continue, In the corresponding unit within the built-in "1" or "0", control and the corresponding jet purge solenoid valve opened and stopped. Continuous Spray and purge solenoid valve open to listen, time stopped in accordance with technological requirements can be arbitrary.System security is to control access to the caps simultaneously tracking, not only accurately detect the electrical switching speed detection, the broken bottles into the bottle and detection switch detection switch three conditions.970GOT human-computer touch-screen terminals operated by the software company's Mitsubishi GT WORKS package, which is a GT Designer with the entire GOT9000 series of graphics software packages. The package is simple, prior to a personal computer simulation on the configurationand debug, after the man-machine operators to download terminals. At the same time, because the man-machine interface and a touch-screen role, will set common switch on the screen to facilitate the operation. And also to increase the number of features, such as setting alarm information.4.After transformation control systemSystem at the normal operation of the machine for automatic control, in accordance with bottles into and out of the bottle for lack or slow pace set by running into the bottle stall bottles, no less than a bottle cap, automatic washing bottles burst, filling automatic back-pressure position , Covered under the system automatically lose covered a stop and safety protection, such as the coordination of action interlock. All the original button after the operation of the touch screen on.5.Detection of the state control system monitoringDetection switch into the bottle and break bottles detection switch bottles of pressure by testing each part of the small metal plates above the location of a photoelectric pulse output, a further PLC acquisition, as each bottle of the pressure above the small metal plates is the location of activities , In the machine running after some time, some pressure above the small bottles of iron tablets and detection switch in the location of displacement, resulting in detection switch mistaken judgement, if not for the judgement of bottles of bottles, bottle explosion Lou Jian, misuse, such as the seizure of output errors So that the PLC have mistaken action, such as a back-pressure, unexploded bottle blowing, washing, stirring cap control system malfunction, such as failure phenomenon.Before the transformation of the daily production process, encountered this phenomenon, the operatives could only switch to thevarious functional or manual control buttons reach the stall so that the equipment work in the absence of monitoring state, the machine lost control function. Caused a lot of production of raw materials such as gas, water, wine waste. Only in the production of intermittent, can be fitter and maintenance electrician in accordance with the detection of small switch on the light-emitting diodes and anti-displacement by adjusting the distance only 5 ~ 8 mm detection switch installation location, and switch to fix detection of small metal plates Gap. This means of detection is very backward, after adjustment reaction to the results, timely response can not be adjusted results.In view of this testing situation, after the transformation of the filling, Gland control system configuration, this part of a new detection and integration in human-computer touch screen, complete bottle of detection.In human-computer touch screen interface on the page display, respectively, at customs, such as electromagnetic motor mixing valve switch state are in different colors to show, very intuitive.Increase the system's functions is to ensure the irrigation of the machine-Gland normal operation of automated control system specifically designed to.6 Concluding remarksAfter the transformation of the control system will greatly simplify the complicated mechanical structure, the running and control of inspection, the degree of automation systems meet the design requirements, greatly reducing the operational strength of the labor so that the shrub-like beer output than in the past Raising more than 30 percent, greatly reduce the failure rate. Embodies the modern equipment of automatic control technology. In the digestion and absorption of today'sindustrial control on the basis of advanced technology innovation, development of domestic technology from the most advanced filling control system.啤酒灌装、压盖机PLC控制系统1. 引言啤酒生产过程分为麦芽制造、麦芽汁制造、前发酵、后发酵、过滤灭菌、包装等几道工序。

外文文献翻译可编程逻辑控制器PLC

百度文库让每个人平等地捉升口我可编程逻辑控制器PLC外文文献翻译(含：英文原文及中文译文)文献出处：Kinna D. Programmable Logic Controllers (PLC) [J]. Fusion Engineering & Design, 2015, 2(12):72-83. 英文原文Programmable Logic Controllers (PLC)Kinna Dari1MotivationProgrammable Logic Controllers (PLC), a computing device invented by Richard E. Morley in 196& have been widely used in industry including manufacturing systems, transportation systems, chemical process facilities, and many others. At that time, the PLC replaced the hardwired logic with soft-wired logic or so-called relay ladder logic (RLL), a programming language visually resembling the hardwired logic, and reduced thereby the configuration time from 6 months down to 6 days [Moody and Morley, 1999].Although PC based control has started to come into place, PLC based control will remain the technique to which the majority of industrial applications will adhere due to its higher performance, lower price, and superior reliability in harsh environments Moreover, according to a studyon the PLC market of Frost and Sullivan [1995], an increase of the annual sales volume to 15 million PLCs per year with the hardware value of more 百度文库让每个人平等地捉升口我than 8 billion US dollars has been predicted, though the prices ofcomputing hardware is steadily dropping. The inventor of the PLC, Richard E Morley, fairly considers the PLC market as a 5-billion industry at the present time.In general, the productivity in generating PLC is far behind compared to other domains, for instance, VLSI design, where efficient computer aided design tools are in practice - Existent software engineering methodologies are not necessarily applicable to the PLC based software design because PLC-programming requires a simultaneous consideration of hardware and software - The software design becomes, thereby, more and more the major cost driver. In many industrial design projects, more than 50% of the manpower allocated for the control system design and installation is scheduled for testing and debugging PLC programs [Rockwell, 1999].PLCs (programmable logic controllers) are the control hubs for a wide variety of automated systems and processes. They contain multiple inputs and outputs that use transistors and other circuitry to simulate switches and relays to control equipment. They are programmable via software interfaced via standard computer interfaces and proprietary languages and network options -Programmable logic controllers I/O channel specifications include total number of points, number of inputs and outputs, ability to expand, and maximum number of channels - Number of points is the sum of the inputs百度文库让每个人平等地捉升口我and the outputs - PLCs may be specified by any possible combination of these values. Expandable units may be stacked or linked together to increase total control capacity. Maximum number of channels refers to the maximum total number of input and output channels in an expanded systemPLC system specifications to consider include scan time, number of instructions, data memory, and program memory. Scan time is the time required by the PLC to check the states of its inputs and outputs. Instructions are standard operations (such as math functions) available to PLC software. Data memory is the capacity for data storage - Program memory is the capacity for control software.Programmable logic controllers use a variety of software programming languages for control. These include IEC 61131-3, sequential function chart (SFC), function block diagram (FBD), ladder diagram (LD), structured text (ST), insti-uction list (IL), relay ladder logic (RLL), flow chart, C, and Basic. The IEC 61131-3 programming environment provides support for five languages specified by the global standard: Sequential Function Chart, Function Block Diagram, Ladder Diagram, Structured Text, and Instruction List. This allows for multi-vendor compatibility and multi-language programming. SFC is a graphical language that provides coordination of program sequences, supporting alternative sequence selections and parallelsequences. FBD uses a broad function library to build complex procedures百度文库让每个人平等地捉升口我in a graphical format - Standard math and logic functions may be coordinated with customizable communication and interface functions. LD is a graphic language for discrete control and interlocking logic. It is completely compatible with FBD for discrete function control. ST is a text language used for complex mathematical procedures and calculations less well suited to graphical languages. IL is a low-level language similar to assembly code - It is used in relatively simple logic instructions. RelayLadder Logic (RLL), or ladder diagrams, is the primary programming language for programmable logic controllers (PLCs) - Ladder logic programming is a graphical representation of the program designed to look like relay logic. Flow Chart is a graphical language that describes sequential operations in a controller sequence or application. It is used to build modular, reusable function libraries.C is a high level programming language suited to handle the most complex computation, sequential, and data logging tasks. It is typically developed and debugged on a PC. BASIC is a high level language used to handle mathematical, sequential, data capturing and interface functions・2ResumeA PLC (programmable Logic Controller) is a device that was invented toreplace the necessary sequential relay circuits for control. The PLC works by looking at its input and depending upon their state, turning on/off its百度文库让每个人平等地捉升口我outputs - The user enters a program, usually via software or programmer, which gives the desired results.PLC is used in many u real world H applications. If there is industry present, chance are good that there is a PLC present. If you are involved in machining, packing, material handling, automated assembly or countless other industries, you are probably already using them. If you are not, you are wasting money and time- Almost any application that needs some typeof electrical control has a need for a PLC -For example, let's assume that when a switch turns on we want to turn a solenoid on for 5 second and then turn it off regardless of how long the switch is on for. We can do this with a simple external timer. But what if the process included 10 switches and solenoids? We should need 10 external times What if the process also needed to count how many times the switch individually turned on? We need a lot of external counters.As you can see the bigger the process the more of a need we have for a PLC - We can simply program the PLC to count its input and turn the solenoids on for the specified time. We will take a look at what is considered to be the H top20" PLC instructions. It can be safely estimated that with a firm understanding of these instructions one can solve more than 80% of the applications in existence・百度文库让每个人平等地捉升口我Of course we will learn more than just this instruction to help you solve almost ALL potential PLC applications.The PLC mainly consists of a CPU, memory areas, and appropriatecircuits to receive input/output data. We can actually consider the PLC to be a box full of hundreds or thousands of separate relay, counters, times and data storage locations, Do these counters, timers, etc. really exist? No, theydon't “physically" exist buE y r simi d atedi and be considered software counters, timers, etc.・These internal relays are simulated through bit locations in registers.What does each part do? Let me tell you.Input RelaysThese are connected to the outside world. They physically exist and receivesignals from switches, sensors. Typically they are not relays but rather they are transistors・Internal Utility RelaysThese do not receive signals from the outside world nor do they physicallyexist, they are simulated relays and are what enables a PLC to eliminate external relays - There are also some special relays that are dedicated to performing only one task. Some are always on while some are always off. Some are on only once during power-on and are typically used for initializing data that was stored.Counters百度文库让每个人平等地捉升口我These again do not physically exist. They are simulated counters and they can be programmed to count pulses. Typically these counters can count up, down or both up and down. Since they are simulated, they are limited in their counting speed - Some manufacturers also include high-speed counters that are hardware based. We think of these as physically existing. Most times these counters can count up, down or up and down.TimersThese also do not physically exist. They come in many varieties and increments. The most common type is an on-delay type. Others include off- delays and both retentive and non-retentive types - Increments vary from1ms through Is.Output RelaysThere are connected to the outside world. They physically exist and send on/off signals to solenoids, lights,etc. They can be transistors, relays, or triacs depending upon the model chosen. Data StorageTypically there are registers assigned to simply store data. They are usually used as temporary storage for math or data manipulation. They can also typically be used to store data when power is removed form the PLC-Upon power-up they will still have the same contents as before power was moved. Very convenient and necessary!A PLC works by continually scanning a program - We can think ofthis scan cycle as consisting of 3 important steps. There are typically more than 3 but we can focus on the important parts and not worry about the others, Typically the others are checking the system and updating the current百度文库让每个人平等地捉升口我internal counter and timer values -Step 1 is to check input status, First the PLC takes a look at each input to determine if it is on off. In other words, is the sensor connected to the first input on? How about the third...It records this data into its memory to be used during the next step.Step 2 is to execute program. Next the PLC executes your program one instruction at a time. Maybe your program said that if the first input was on then it should turn on the first output. Since it already knows which inputs are on/off from the previous step, it will be able to decide whether the first output should be turned on based on the state of the first input. It will store the execution results for use later during the next step.Step 3 is to update output status. Finally the PLC updates the status the outputs. It updates the outputs based on which inputs were on during the first step and the results executing your program during the second step. Based on the example in step 2 it would now turn on the first output because the first input was on and your program said to turn on the first output when this condition is true.After the third step the PLC goes back to step one repeats the stepscontinuously. One scan time is defined as the time it takes to execute the 3 steps continuously. One scan time is defined as the time it takes to execute the 3 steps listed above - Thus a practical system is controlled to perform specified operations as desired.百度文库让每个人平等地捉升口我3PLC StatusThe lack of keyboard and other input-output devices is very noticeable on a PLC. On the front of the PLC there are normally limited status lights. Common lights indicate.These lights are normally used for debugging. Limited buttons will also be provided for PLC hardware. The most common will be a run/program switch that will be switched to program when maintenance is being conducted, and back to run when in production. This switch normally requires a key to keep unauthorized personnel from altering the PLC program or stopping execution. A PLC will almost never have an on-off switch or reset button on the front. This needs to be designed into the remainder of the system.The status of the PLC can be detected by ladder logic also. It is common for programs to check to see if they are being executed for the first time, as shown in Figure 1. Hie first seal input will be tme on the very first time the ladder logic is scanned, but false on every other scan. In this case the address for 'first scan' in a PLC-5 is ,S2:1/14\ With the logic in the example the first scan will seal on light ；until , cleaF is turned on. So thelight will turn on after the PLC has been turned on, but it will turn off and stay off after 'cleaF is tiinied on.百度文库让每个人平等地捉升自我4Memory TypesThere are a few basic types of computer memory that are in use today.RAM (Random Access Memory) - this memory is fast, but it will lose its contents when power is lost, this is known as volatile memory. Every PLC uses this memory for the central CPU when running the PLC -ROM (Read Only Memory) - this memory is permanent and cannot be erased. It is often used for storing the operating system for the PLC -EPROM (Erasable Programmable Read Only Memory) - this is memory that can be programmed to behave like ROM, but it can be erased with ultraviolet light and reprogrammed・EEPROM (Electronically Erasable Programmable Read Only Memory) -This memory can store programs like ROM - It can be programmed and erased using a voltage, so it is becoming more popular than EPROMs.All PLCs use RAM for the CPU and ROM to store the basic operating system for the PLC - When the power is on the contents of the RAM will be kept, but the issue is what happens when power to the memory is lost. Originally PLCvendors used RAM with a battery so that the memory contents would not be lost if the power was lost. This method is still in use, but is losing favor. EPROMs have also been a popular choice for programming PLCs. The EPROM is programmed out of the PLC, and then placed in the PLC. When the PLC is turned on the ladder logic program on10百度文库让每个人平等地捉升口我the EPROM is loaded into the PLC and run. This method can be very reliable, but the erasing and programming technique can be time consuming - EEPROM memories are a permanent part of the PLC, and programs canbe stored in them like EPROM. Memory costs continue to drop, and newer types (such as flash memory) are becoming available, and these changes will continue to impact PLCs.5Objective and Significance of the ThesisThe objective of this thesis is to develop a systematic software design methodology for PLC operated automation systems. The design methodology involves high-level description based on state transition models that treat automation control systems as discrete event systems, a stepwise design process, and set of design rules providing guidance and measurements to achieve a successful design. The tangible outcome of this research is to find a way to reduce the uncertainty in managing the control software development process,that is, reducing programming and debugging time and their variation, increasing flexibility of the automation systems, and enabling software reusability through modularity. The goal is to overcome shortcomings of current programming strategies that are based on the experience of the individual software develope 匚中文译文可编程逻辑控制器(PLC)吉娜达尔11百度文邮-让每个人平零地捉开口我1动机可编程逻辑控制器（PLC）是Richard E. Morley于1968年发明的计算设备，己广泛应用于工业领域，包括制造系统，运输系统，化学处理设施等等。

关于PLC的外文及翻译

PLCs --Past, Present and FutureEveryone knows there's only one constant in the technology world, and that's change. This is especially evident in the evolution of Programmable Logic Controllers (PLC) and their varied applications. From their introduction more than 30 years ago, PLCs have become the cornerstone of hundreds of thousands of control systems in a wide range of industries.At heart, the PLC is an industrialized computer programmed with highly specialized languages, and it continues to benefit from technological advances in the computer and information technology worlds. The most prominent of which is miniaturization and communications.The Shrinking PLCWhen the PLC was first introduced, its size was a major improvement - relative to the hundreds of hard-wired relays and timers it replaced. A typical unit housing a CPU and I/O was roughly the size of a 19 television set. Through the 1980s and early 1990s, modular PLCs continued to shrink in footprint while increasing in capabilities and performance (see Diagram 1 for typical modular PLC configuration).In recent years, smaller PLCs have been introduced in the nano and micro classes that offer features previously found only in larger PLCs. This has made specifying a larger PLC just for additional features or performance, and not increased I/O count, unnecessary, as even those in the nano class are capable of Ethernet communication, motion control, on-board PID with autotune, remote connectivity and more.PLCs are also now well-equipped to replace stand-alone process controllers in many applications, due to their ability to perform functions of motion control, data acquisition, RTU (remote telemetry unit) and even some integrated HMI (human machine interface) functions. Previously, these functions often required their own purpose-built controllers and software, plus a separate PLC for the discrete control and interlocking.The Great CommunicatorPossibly the most significant change in recent years lies in the communications arena. In the 1970s Modicon introduction of Modbus communications protocol allowed PLCs to communicate over standard cabling. This translates to an ability to place PLCs in closer proximity to real world devices and communicate back to other system controls in a main panel.In the past 30 years we have seen literally hundreds of proprietary and standard protocols developed, each with their own unique advantages.Today's PLCs have to be data compilers and information gateways. They have to interface with bar code scanners and printers, as well as temperature and analog sensors. They need multiple protocol support to be able to connect with other devices in the process. And furthermore, they need all these capabilities while remaining cost-effective and simple to program.Another primary development that has literally revolutionized the way PLCs are programmed, communicate with each other and interface with PCs for HMI, SCADA or DCS applications, came from the computing world.Use of Ethernet communications on the plant floor has doubled in the past five years. While serial communications remain popular and reliable, Ethernet is fast becoming the communications media of choice with advantages that simply can't be ignored, such as: * Network speed. * Ease of use when it comes to the setup and wiring. * Availability of off-the-shelf networking components. * Built-in communications setups.Integrated Motion ControlAnother responsibility the PLC has been tasked with is motion control. From simple open-loop to multi-axis applications, the trend has been to integrate this feature into PLC hardware and software.There are many applications that require accurate control at a fast pace, but not exact precision at blazing speeds. These are applications where the stand-alone PLC works well. Many nano and micro PLCs are available with high-speed counting capabilities and high-frequency pulse outputs built into the controller, making them a viable solution for open-loop control.The one caveat is that the controller does not know the position of the output device during the control sequence. On the other hand, its main advantage is cost. Even simple motion control had previously required an expensive option module, and at times was restricted to more sophisticated control platforms in order to meet system requirements.More sophisticated motion applications require higher-precision positioning hardware and software, and many PLCs offer high-speed option modules that interface with servo drives. Most drives today can accept traditional commands from host (PLC or PC) controls, or provide their own internal motion control. The trend here is to integrate the motion control configuration into the logic controller programming software package.Programming LanguagesA facet of the PLC that reflects both the past and the future is programming language. The IEC 61131-3 standard deals with programming languages and defines two graphical and two textual PLC programming language standards: * Ladder logic (graphical). * Function block diagram (graphical). * Structured text(textual).Instruction list (textual).This standard also defines graphical and textual sequential function chart elements to organize programs for sequential and parallel control processing. Based on the standard, many manufacturers offer at least two of these languages as options for programming their PLCs. Ironically, approximately 96 percent of PLC users recently still use ladder diagrams to construct their PLC code. It seems that ladder logic continues to be a top choice given it's performed so well for so long.Hardware PlatformsThe modern PLC has incorporated many types of Commercial off the Shelf (COTS) technology in its CPU. This latest technology gives the PLC a faster, more powerful processor with more memory at less cost. These advances have also allowed the PLC to expand its portfolio and take on new tasks like communications, data manipulation and high-speed motion without giving up the rugged and reliable performance expected from industrial control equipment.New technology has also created a category of controllers called Programmable Automation Controllers, or PACs. PACs differ from traditional PLCs in that they typically utilize open, modular architectures for both hardware and software, using de facto standards for network interfaces, languages and protocols. They could be viewed as a PC in an industrial PLC-like package.The FutureA 2005 PLC Product Focus Study from Reed Research Group pointed out factors increasingly important to users, machine builders and those making the purchasing decisions. The top picks for features of importance were.* The ability to network, and do so easily. Ethernet communications is leading the charge in this realm. Not only are new protocols surfacing, but many of the industry de facto standard serial protocols that have been used for many years are being ported to Ethernet platforms. These include Modbus (ModbusTCP), DeviceNet (Ethernet/IP) and Profibus (Profinet). Ethernet communication modules for PLCs are readily available with high-speed performance and flexible protocols. Also, many PLC CPUs are now available with Ethernet ports on board, saving I/O slot space. PLCs will continue to develop more sophisticated connectivity to report information to other PLCs, system control systems, data acquisition (SCADA) systems and enterprise resource planning (ERP) systems. Additionally, wireless communications will continue to gain popularity.* The ability to network PLC I/O connections with a PC. The same trends that have benefited PLC networking have migrated to the I/O level. Many PLC manufacturers are supporting the most accepted fieldbus networks, allowing PLC I/O to be distributed over large physical distances, or located where it was previously considered nearly impossible. This has opened the door for personal computers to interface with standard PLC I/O subsystems by using interface cards, typically supplied by the PLC manufacturer or a third party developer. Now these challenging locations can be monitored with today a PC. Where industrial-grade control engines are not required, the user can take advantage of more advanced software packages and hardware flexibility at a lower cost.* The ability to use universal programming software for multipletargets/platforms. In the past it was expected that an intelligent controller would be complex to program. That is no longer the case. Users are no longer just trained programmers, such as design engineers or systems integrators, but end-users who expect easier-to-use software in more familiar formats. The Windows-based look and feel that users are familiar with on their personal computers have become the most accepted graphical user interface. What began as simple relay logic emulation for programming PLCs has evolved into languages that use higher level function blocks that are much more intuitive to configure. PLC manufacturers are also beginning to integrate the programming of diverse functions that allow you to learn only one package in configuring logic, HMI, motion control and other specialized capabilities. Possibly the ultimate wish of the end-user would be for a software package that could seamlessly program many manufacturers PLCs and sub-systems. After all, Microsoft Windows operating system and applications work similarly whether installed on a Dell, HP or IBM computer, which makes it easier for the user.Overall, PLC users are satisfied with the products currently available, while keeping their eye on new trends and implementing them where the benefits are obvious. Typically, new installations take advantage of advancing technologies, helping them become more accepted in the industrial world.PLC的过去、现在与未来众所周知，科技世界里只有一个永恒真理，那就是变化。

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