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本文部分内容来自网络，本司不为其真实性负责，如有异议请及时联系，本司将予以删除== 本文为word格式，简单修改即可使用，推荐下载！ ==plc英文参考文献a water pumping control system with a programmablelogic controller (plc) and industrial wireless modules for industrial plants—an experimental setupisa transactions, in press, corrected proof, available online 3 december XXramazan bayindir, yucel cetince《电气控制与plc》参考文献参考文献[1] 张凤珊.电气控制及可编程序控制器.2版 [m].北京: 中国轻工业出版社，XX.[2] 《工厂常用电气设备手册》编写组.工厂常用电气设备手册.2版 [m].北京: 中国电力出版社，1998.[3] 马志溪.电气工程设计 [m].北京: 机械工业出版社，XX.[4] 刘增良，刘国亭.电气工程cad [m].北京: 中国水利水电出版社，XX.[5] 齐占庆，王振臣.电气控制技术 [m].北京: 机械工业出版社，XX.[6] 史国生.电气控制与可编程控制器技术 [m].北京: 化学工业出版社，XX.[7] 郁汉琪.电气控制与可编程序控制器应用技术 [m].南京: 东南大学出版社，XX.[8] 张万忠.可编程控制器应用技术 [m].北京: 化学工业出版社，XX.[9] 王兆义.小型可编程控制器实用技术 [m].北京: 机械工业出版社，XX.[10] 三菱微型可编程控制器手册 [m].mitsubishi socio-tech，XX.[11] 吴晓君，杨向明.电气控制与可编程控制器应用 [m].北京: 中国建材工业出版社，XX.[12] 李道霖.电气控制与plc原理及应用 [m].北京: 电子工业出版社，XX.[13] s7-200 cn可编程序控制器手册 [m].西门子(中国)有限公司自动化与驱动集团，XX.[14] siemens wincc手册 [m].西门子(中国)有限公司自动化与驱动集团，XX.[15] 魏艳君.多功能屋面sp板切割机 [j].机电一体化，XX，(4)：47-48.以下文字仅用于测试排版效果, 请使用时删除！“山不在高，有仙则灵。
英文文献-可编程逻辑控制器(PLC)英语
Programmable Logic ControllersProgrammable logic controller (plc) is a solid-state device used to control machine motion or process operation by means of a stored program. The PLC sends output control signals and receives input signals through input/output (I/O) devices. A PLC controls outputs in response to stimuli at the inputs according to the logic prescribed by the stored program. The inputs are made up of limit switches, pushbuttons, thunbwheels. Switches, pulses, analog signals, ASCLL serial data, and binary or BCD data from absolute position encoders. The outputs are voltage or current levels to drive end devices such as solenoids, motor starters, relays, lights, and so on. Other output devices include analog devices, digital BCD displays, ASCII compatible devices, servo variable-speed drives, and even computers.Programmable controllers were developed (circa in 1968) when General Motors Corp, and other automobile manufacturers were experimenting to see if there might be an alternative to scrapping all their hardwired control panels of machine tools and other production equipment during a model changeover. This annual tradition was necessary because rewiring of the panels was more expensive than buying new ones.The automotive companies approached a number of control equipment manufacturers and asked them to develop a control system that would have a longer productive life without major rewiring, but would still be understandable to and repairable by plant personnel. The new product was named a “pr ogrammable controller”.The processor part of the PLC contains a central processing unit and memory。
关于PLC的英文文献Word版
1. PROGRAMMABLE LOGIC CONTROLLERS1.1 INTRODUCTIONControl engineering has evolved over time. In the past humans was the main method for controlling a system. More recently electricity has been used for control and early electrical control was based on relays. These relays allow power to be switched on and off without a mechanical switch. It is common to use relays to make simple logical control decisions. The development of low cost computer has brought the most recent revolution, the Programmable Logic Controller (PLC). The advent of the PLC began in the 1970s, and has become the most common choice for manufacturing controls. PLC have been gaining popularity on the factory floor and will probably remain predominant for some time to come. Most of this is because of the advantages they offer.. Cost effective for controlling complex systems.. Flexible and can be reapplied to control other systems quickly and easily.. Computational abilities allow more sophisticated control.. Trouble shooting aids make programming easier and reduce downtime. . Reliable components make these likely to operate for years before failure.1.2 Ladder LogicLadder logic is the main programming method used for PLC. As mentioned before, ladder logic has been developed to mimic relay logic. The decision to use the relay logic diagrams was a strategic one. By selecting ladder logic as the main programming method, the amount of retraining needed for engineers and trades people was greatly reduced. Modern control systems still include relays, but these are rarely used for logic.A relay is a simple device that uses a magnetic field to control a switch, as pictured in Figure 2.1. When a voltage is applied to the input coil, the resulting current creates a magnetic field. The magnetic field pullsa metal switch (or reed) towards it and the contacts touch, closing the switch. The contact that closes when the coil is energized is called normally open. The normally closed contacts touch when the input coil is not energized. Relays are normally drawn in schematic form using a circle to represent the input coil. The output contacts are shown with two parallel lines. Normally open contacts are shown as two lines, and will be open (non-conducting) when the input is not energized. Normally closed contacts are shown with two lines with a diagonal line through them. When the input coil is not energized the normally closed contactswill be closed (conducting).Relays are used to let one power source close a switch for another (often high current) power source, while keeping them isolated. An example of a relay in a simple control application is shown in Figure 2.2. In this system the first relay on the left is used as normally closed, and will allow current to flow until a voltage is applied to the input A. The second relay is normally open and will not allow current to flow until a voltage is applied to the input B. If current is flowing through the first two relays then current will flow through the coil in the third relay, and close the switch for output C. This circuit would normally be drawn in the ladder logic form. This can be read logically as C will be on if A is off and B is on.1.3 ProgrammingThe first PLC were programmed with a technique that was based on relay logic wiring schematics. This eliminated the need to teach the electricians, technicians and engineers how to program a computer - but, this method has stuck and it is the most common technique for programming PLC today. An example of ladder logic can be seen in Figure 2.5. To interpret this diagram imagines that the power is on the vertical line on the left hand side, we call this the hot rail. On the right hand side is the neutral rail. In the figure there are two rungs, and on each rung there are combinations of inputs (two vertical lines) and outputs (circles). If the inputs are opened or closed in the right combination the power can flow from the hot rail, through the inputs, to power the outputs, and finally to the neutral rail. An input can come from a sensor, switch, or any other type of sensor. An output will be some device outside the PLC that is switched on or off, such as lights or motors. In the toprung the contacts are normally open and normally closed, which means if input A is on and input B is off, then power will flow through the output and activate it. Any other combinationof input values will result in the output X being off.The second rung of Figure 2.5 is more complex, there are actually multiple combinations of inputs that will result in the output Y turning on. On the left most part of the rung, power could flow through the top if C is off and D is on. Power could also (and simultaneously) flow through the bottom if both E and F are true. This would get power half way across the rung, and then if G or H is true the power will be delivered to output Y. In later chapters we will examine how to interpret and construct these diagrams. There are other methods for programming PLC. One of the earliest techniques involved mnemonic instructions. These instructions can be derived directly from the ladder logic diagrams and entered into the PLC through a simple programming terminal. An example of mnemonics is shown in Figure 2.6. In this example the instructions are read one line at a time from top to bottom. The first line 00000 has the instruction LDN (input load and not) for input 00001. This will examine the inputto the PLC and if it is off it will remember a 1 (or true), if it is on it will remember a 0 (or false). The next line uses an LD (input load) statement to look at the input. If the input is off it remembers a 0, if the input is on it remembers a 1 (note: this is the reverse of the LD). TheAND statement recalls the last two numbers remembered and if they are both true the result is a 1; otherwise the result is a 0. This result now replaces the two numbers that were recalled, and there is only one number remembered. The process is repeated for lines 00003 and 00004, but when these are done there are now three numbers remembered. The oldest number is from the AND, the newer numbers are from the two LD instructions. The AND in line 00005 combines the results from the last LD instructions and now there are two numbers remembered. The OR instruction takes the two numbers now remaining and if either one is a 1 the result is a 1, otherwise the result is a 0. This result replaces the two numbers, and there is now a single number there. The last instruction is the ST (store output) that will look at the last value stored and if it is 1, the output will be turned on; if it is 0 the output will be turned off.The ladder logic program in Figure 2.6, is equivalent to the mnemonic program. Even if you have programmed a PLC with ladder logic, it will be converted to mnemonic form before being used by the PLC. In the past mnemonic programming was the most common, but now it is uncommon for users to even see mnemonic programs.Sequential Function Charts (SFC) have been developed to accommodate the programming of more advanced systems. These are similar to flowcharts, but much more powerful. The example seen in Figure 2.7 is doing two different things. To read the chart, start at the top where is says start. Below this there is the double horizontal line that says follow both paths. As a result the PLC will start to follow the branch on the left and right hand sides separately and simultaneously. On the left there are two functions the first one is the power up function. This function will run until it decides it is done, and the power down function will come after. On the right hand side is the flash function; this will run until it is done. These functions look unexplained, but each function, such as power up will be a small ladder logic program. This method is much different from flowcharts because it does not have to follow a single path through the flowchart.Structured Text programming has been developed as a more modern programming language. It is quite similar to languages such as BASIC.A simple example is shown in Figure 2.8. This example uses a PLC memory location N7:0. This memory location is for an integer, as will be explained later in the book. The first line of the program sets the value to 0. The next line begins a loop, and will be where the loop returns to. The next line recalls the value in location N7:0, adds 1 to it and returns it to the same location. The next line checks to see if the loop should quit. If N7:0 is greater than or equal to 10, then the loop will quit, otherwise the computer will go back up to the REPEAT statement continue from there. Each time the program goes through this loop N7:0 will increase by 1 until the value reaches 10.N7:0 := 0;REPEATN7:0 := N7:0 + 1;UNTIL N7:0 >= 10END_REPEAT;2. PLC ConnectionsWhen a process is controlled by a PLC it uses inputs from sensors to make decisions and update outputs to drive actuators, as shown in Figure 2.9. The process is a real process that will change over time. Actuators will drive the system to new states (or modes of operation). This means that the controller is limited by the sensors available, if an input is not available, the controller will have no way to detect a condition.The control loop is a continuous cycle of the PLC reading inputs, solving the ladder logic, and then changing the outputs. Like any computer this does not happen instantly. Figure 2.10 shows the basic operation cycle of a PLC. When power is turned on initially the PLC does a quick sanity check to ensure that the hardware is working properly. If there is a problem the PLC will halt and indicate there is an error. For example, if the PLC backup battery is low and power was lost, the memory will be corrupt and this will result in a fault. If the PLC passes the sanity checks it will then scan (read) all the inputs. After the inputs values are stored in memory the ladder logic will be scanned (solved) using the stored values - not the current values. This is done to prevent logic problems when inputs change during the ladder logic scan. When the ladder logic scan is complete the outputs will be scanned (the output values will be changed). After this the system goes back to do a sanity check, and the loop continues indefinitely. Unlike normal computers, the entire program will be run every scan. Typical times for each of the stages are in the order of milliseconds.3. SUMMARY. Normally open and closed contacts.. Relays and their relationship to ladder logic.. PLC outputs can be inputs, as shown by the seal in circuit.. Programming can be done with ladder logic, mnemonics, SFC, and structured text.. There are multiple ways to write a PLC program.（注：可编辑下载，若有不当之处，请指正，谢谢!）。
关于plc的母料称量控制系统设计英文参考文献
关于plc的母料称量控制系统设计英文参考文献Designing a PLC-based Ingredient Weighing Control System: A ReferenceThe efficient and precise control of ingredient weighing is a crucial aspect in various industrial processes, particularly in the manufacturing of food, pharmaceuticals, and chemical products. The use of Programmable Logic Controllers (PLCs) has become a widely adopted approach to automate and optimize these weighing processes, ensuring consistent product quality and enhancing overall production efficiency.In this reference, we will explore the design of a PLC-based ingredient weighing control system, highlighting the key components, operational principles, and implementation strategies to serve as a guide for engineering professionals and researchers in the field.System Architecture and ComponentsThe PLC-based ingredient weighing control system typically consistsof the following essential components:1. PLC: The Programmable Logic Controller serves as the central processing and control unit, responsible for executing the programmed logic, managing input/output signals, and coordinating the overall system operation.2. Load cells: These are precision sensors that convert the weight of the ingredients into electrical signals, providing the PLC with the necessary weight data for accurate monitoring and control.3. Weighing vessel or hopper: The container or platform where the ingredients are placed for weighing, with the load cells strategically positioned to measure the weight accurately.4. Actuators: Electromechanical devices, such as motors, valves, or solenoids, that are controlled by the PLC to perform actions like opening/closing ingredient feed gates, adjusting flow rates, or triggering ingredient discharge.5. Human-Machine Interface (HMI): A user interface, typically a touchscreen or display panel, that allows operators to monitor the system status, input process parameters, and perform manual adjustments as needed.6. Communication interfaces: Networking protocols and communication modules that enable the PLC to exchange data with other systems, such as higher-level control systems or enterprise-level software.Operational PrinciplesThe PLC-based ingredient weighing control system operates based on the following principles:1. Ingredient loading: The ingredients are loaded into the weighing vessel or hopper, and the load cells continuously measure the weight of the contents.2. Weight monitoring and comparison: The PLC reads the weight data from the load cells and compares it against the target or desired weight for each ingredient, as defined in the control program.3. Feedback control: Based on the weight deviation, the PLC issues control commands to the actuators, such as opening or closing ingredient feed gates, to maintain the target weight within the specified tolerance.4. Batch completion: Once the target weight for each ingredient is reached, the PLC triggers the discharge of the batch and prepares the system for the next weighing cycle.5. Monitoring and reporting: The PLC continuously monitors the system status, including weight data, process parameters, and any fault or error conditions. This information can be displayed on the HMI and/or communicated to higher-level systems for further analysis and reporting.Implementation StrategiesTo effectively implement a PLC-based ingredient weighing control system, the following strategies can be considered:1. Modular design: Adopting a modular approach in the system architecture allows for flexibility, scalability, and easier maintenance. This can be achieved by using standardized PLC modules, distributed I/O, and easily configurable communication interfaces.2. Precise calibration: Accurate calibration of the load cells and weighing vessel/hopper is crucial to ensure reliable weight measurements. This may involve the use of calibration procedures, test weights, and periodic recalibration to maintain system accuracy over time.3. Failsafe mechanisms: Incorporating failsafe mechanisms, such as redundant sensors, backup power supplies, and emergency stop functions, can enhance the system's reliability and prevent potentialproduction disruptions.4. Data integration and analysis: Integrating the PLC-based system with enterprise-level software or data management platforms can enable comprehensive data collection, reporting, and analytical capabilities. This can support quality control, process optimization, and predictive maintenance strategies.5. Operator training and user-friendly interfaces: Providing comprehensive operator training and designing intuitive HMI interfaces can improve system usability, reduce the risk of operational errors, and facilitate efficient system monitoring and control.ConclusionThe design of a PLC-based ingredient weighing control system is a critical aspect of many industrial processes, ensuring accurate, reliable, and efficient ingredient handling and dosing. By leveraging the capabilities of Programmable Logic Controllers, engineers and researchers can develop advanced weighing systems that enhance product quality, increase production throughput, and optimize resource utilization. The strategies and principles outlined in this reference can serve as a valuable guide for the successful implementation of such systems in various manufacturing and processing industries.。
PLC及变频器技术论文中英文资料对照外文翻译文献综述
PLC及变频器技术中英文资料对照外文翻译文献综述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 each industrial 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 networkconstitution 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 technology and 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 andreliability 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 customers and 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 PWMinverter 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. Although because 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英文文献
ONE、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 dedicatedcontrol 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 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 `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. Thoughthe 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 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, the power 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 operation.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 for 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 forma 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 amemory 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 220 VAC. On some PLC controllers you‟ll find electrical supply as a separate module. 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 controlsystems 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.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 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 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.Five、AK 1703 ACPFollowing the principle of our product development, AK 1703 ACP has high functionality and flexibility, through the implementation of innovative and reliable technologies, on the stable basis of a reliable product platform.For this, the system concept ACP (Automation, Control and Protection) creates the technological preconditions. Balanced functionality permits the flexible combination of automation, telecontrol and communication tasks. Complemented with the scalable performance and various redundancyconfigurations, an optimal adaptation to the respective requirements of the process is achieved.AK 1703 ACP is thus perfectly suitable for automation with integrated telecontrol technology as:•Telecontrol substation or central device•Automation unit with autonomous functional groups•Data node, station control device, front-end or gateway•With local or remote peripherals•For rear panel installation or 19 inch assembly•Branch-neutral product, therefore versatile fields of application and high productstability•Versatile communication•Easy engineering•Plug & play for spare parts•Open system architecture•Scalable redundancy•The intelligent terminal - TM 1703The Base Unit AK 1703 ACP with Peripheral Elements has one basic system element CP-2010/CPC25 (Master control element) and CP-2012/PCCE25 (Processing and communication element) ,one bus line with max. 16 peripheral elements can be connected.CP-2010/CPC25 Features and FunctionsSystem Functions:•Central element,coordinating all system servicesCentral hub function for all connected basic system elements•Time managementCentral clock of the automation unitSetting and keeping the own clock`s time with a resolution of 10ms Synchronization via serid communication via LAN or local•RedundancyVoting and change-over for redundant processing and communication elements of the own automation unitSupports voting and change-over by an external SCA-RS redundancy switch Supports applicational voting and change-over by an external system,e.g.a control system•SAT TOLLBOX|| connectionStoring firmware and parameters on a Flash CardCommunication:•Communication via installable protocol elements to any superior or subordinate automation unit•Automatic data flow routing•Priority based data transmission (priority control)•Own circular buffer and process image for each connected station(data keeping)•Redundant communication routesCommunication with redundant remote stations•Special application specific functions for dial-up trafficTest if stations are reachableProcess Peripherals:•Transmission of spontaneous information objects from and to peripheral elements, via the serial Ax 1703 peripheral busFunctions for Automation:•Open-/closed-loop control function for the execution of freely definable user programs which are created with CAEX plus according to IEC 61131-3,ing function diagram technology 512KB for user programApprox 50.000 variables and signals,2.000 of them retainedCycle of 10ms or a multiple thereofOnline testLoadable without service interruption•Redundant open-/closed-loop control functionsSynchronization via redundancy linkTransmission of periodic process information between the open-/closed-loop control function and the peripheral elements,via the serial Ax 1703 peripheral bus.Six、SIEMENS PLCSIMATIC S7-300 series PLC applied to all walks of life and various occasions in the detection, monitoring and control of automation, its power to both the independent operation of, or connected to a network able to achieve complex control.The photoelectric products with isolation, high electromagnetic compatibility; have high industrial applicability, allowing the ambient temperature of 60 ℃; has strong anti-jamming and anti-vibration and impact resistance, so in a harsh working environment has been widely Applications.I also mean freedom of communication S7-300 type PLC' s a very unique feature, which allows S7-300-PLC can deal openly with any other communications equipment, communications controller, or PLC S7-300 type can be defined by the user's own Communications protocol (of the agreement ASCII), the baud rate to 1.5 Mbit / s (adjustable). So that can greatly increase the scope of communications so that the control system configuration more flexible and convenient. Of any kind with a serial interface peripherals, such as: printers or bar code readers, Drives, a modem (Modem), the top PC-connected, and so can be used. Users can program to develop communication protocols, the exchange of data (for example: ASCII character code), RS232 interfaces with the equipment can also be used PC / PPI cable linking the free communication communications. When the PC offline, under the control of the next crew, the whole system can operate normally.PC that is by control centre, mainly by the PC and laser printer components, using SIMATIC WINCC software platform, the all-Chinese interface, friendly man-machine dialogue. Managers and operators can be observed through a PC,shown in the various kinds of information to understand the present and pion tasks.WINCC and the ice-storage operation of the automatic control system and all the parameters, and through the mouse to print equipment management and implement at software in the field of automation can be used for all the operators‟control and monitoring tasks. Can be controlled in the process of the events clearly show, and shows the current status and order records, the recorded data can show all or select summary form, or may be required for editing, printing and output statements and trends .WINCC able to control the critical situation in the early stages of the report, and the signal can be displayed on the screen, can also use sound to be felt. It supported by online help and operational guidelines to eliminate failure. WINCC a workstation can be devoted to the process control to the process so that important information not is shielded. Software-assisted operation strategy ensures that the process was not illegal to visit and to provide for non-industrial environment in the wrong operation.WINCC is MICRSOFT WINDOWS98 or WINDOWS NT4.0 operating system,running on a PC object-oriented class 32-bit applications, OLE through the window and ODBC standard mechanism, as an ideal partner to enter the communications world WINDOWS, it can be easily WINCC To integrate a company-wide data processing system.Seven、CommunicationsCommunications are vital to an individual automation cell and to the automated factory as a whole. We've heard a lot about MAP in the last few years, and a lot of companies have jumped on the band wagon. Many, however were disappointed when a fully-defined and completed MAP specification didn’t appear immediately. Says Larry Kumara:”Right now , MAP is still a moving target for the manufacturers specification that is not final. Presently, for example, people are introducing products to meet the MAP 2.1standard.Yet 2.1-basedproducts will be obsolete when the new standard for MAP,3.0 is introduced.”Because of this, many PLC vendors are holding off on full MAP implementations. Omron, for example has an ongoing MAP-compatibility program, but Frank Newborn, vice president of Omron‟s Industrial Division, reports that because of the lack of a firm definition, Omron's PLCs don't yet talk to MAP.Since it‟s unlikely that an individual PLC would talk to broadband MAP anyway, makers are concentrating n proprietary networks. According to Sal Provanzano, users fear that if they do get on board and vendors withdraw from MAP, they’ll pulse width modulation control system be the ones left holding a communications structure that‟s not supported.。
plc论文参考文献(精选)
plc论文参考文献（精选）plc论文参考文献（精选）本文关键词：参考文献，精选，论文，plc plc论文参考文献（精选）本文简介：随着计算机技术、信号处理技术、控制技术、网络技术的不断发展和用户需求的不断提高，PLC的软硬件水平与规模也发生了质与量的变化，今天的PLC不再局限于逻辑控制，在运动控制、过程控制等领域也发挥着十分重要的作用。
以下是我们整理的一些plc论文参考文献，希望对你论文的写作有所帮助。
plc论文参考文plc论文参考文献（精选）本文内容：随着计算机技术、信号处理技术、控制技术、网络技术的不断发展和用户需求的不断提高，PLC的软硬件水平与规模也发生了质与量的变化，今天的PLC不再局限于逻辑控制，在运动控制、过程控制等领域也发挥着十分重要的作用。
以下是我们整理的一些plc论文参考文献，希望对你论文的写作有所帮助。
plc论文参考文献一：[1]王前进，马小平，张守田。
PLC软冗余在通风机监控系统中的应用[J].工矿自动化，2014,40（01）：93-96.[2]王云刚，陈文燕。
基于MCGS和PLC的水位自动控制系统[J].测控技术，2014,33（01）：96-98+103.[3]周石强，郭强，朱涛，刘旭东。
电气控制与PLC应用技术的分析研究[J].中华民居（下旬刊），2014（01）：199+201.[4]袁文波，洪波，尤万方，殷召生，蒋彦，温柳。
S7-PLC基于Modbus/TCP协议通信研究[J].计算机工程与设计，2014,35（02）：736-741.[5]谢劲松，梁宏斌。
五轴数控铣床软PLC控制系统的研究[J].组合机床与自动化加工技术，2014（03）：82-85.[6]李本红，陈小军。
基于PLC和触摸屏的食品包装自动化生产线控制系统设计[J].机电工程技术，2014,43（01）：9-13.[7]胡世军，张红香，张代录。
PLC应用于温度控制系统的研究[J].锻压技术，2014,39（01）：118-120.[8]刘力。
plc英文文献
1. CONVEYOR SYSTEMS Conveyor systems are often modular in nature and can be built up from basic units (or primitives) such as linear conveyor modules, either belt or roller type, and connecting devices such as lift stations and conveyor junction modules. Complex conveyor systems can easily be configured from combinations of these standard modules. Modules are available from a range of vendors in a wide portfolio of styles and varieties [1]. Conventional conveyor systems are typically installed as simple straight assembly lines and a number of workplaces are set on each side of the conveyor for manual and/or automated operations. For simple configurations of this type, the design and implementation is a relatively trivial task. Control programs are easily designed and coded using conventional Ladder Logic Diagrams (LLDs) which can be executed by Programmable Logic Controllers (PLCs) [2]. However, today's demands for multi-product mixes and flexibility for quick system reconfiguration can require more complex conveyor systems. Traditional types of sequentially controlled conveyor installations are often found to be too rigid for such demanding operational requirements. Conveyor systems which support multiple product mixes and variable product 799
(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英文文献.pdf
Plc SynopsisCentral Processing Unit(CPU)is the brain of a PLC controller.CPU itself is usually one of the microcontrollers.Aforetime these were8-bit microcontrollers such as8051,and now these are16-and32-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.PLC controllers have complex routines for memory checkup in order to ensure that PLC memory was not damaged(memory checkup is done for safety reasons).Generally speaking,CPU unit makes a great number of check-ups of the PLC controller itself so eventual errors would be discovered early.You can simply look at any PLC controller and see that there are several indicators in the form.of light diodes for error signalization. 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 forma 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 anytechnician(and not just a person who developed the system)to understand a ladder diagram right ments 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 at24VDC or220VAC.On some PLC controllers you’ll find electrical supply as a separate module.Those are usually bigger PLC controllers,while small and medium series already contain the supply er 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 er 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二Opening and based on the industry PC controlThe PLC manufacturer already started to gaze at the formidable impact which brings based on the industry PC control technology.Some experts even believed that the new commercial activity brings new technical and the opening technology standard will bury traditional PLC.The PLC manufacturer believed that although has the massive PLC control device in the industry field installation,but they still needed to unite the labor to control the software company,with the aim of developing them based on the industry PC process control software.Indeed,several years ago have the new old PLC mix use obviously in the industry scene the situation,the industrial user can not but simultaneously study the related new old knowledge,even each other profits from the study.The majority PLC manufacturers have provided the soft logic and one kind of service platform merely for the industrial user.In the high-end application aspect,very difficult to further differentiate the PLC control system and between the industry PC control system's difference,because this both have used the similar type microprocessor and the memory chip.Makes an analogy vividly,if you forget industry PC and in the PLC these words and expressions wording meaning,then can observe in the box is some basic computer hardware technology exactly,we observe are actually these basic strokes complication and the mixture,these technologies are combined effectively in the control systemMoreover,uses the opening control the reason is the system function integration need at the same time,on the other hand is also because some industrial user makes excessive demands the result excessively to the function.If can give the high value,can obtain the more basic strokesknowledge.The PLC manufacturer concentrates the system functionalization,but the industrial user concentrates the system application.The people may see that future trend of development will be further integrates more functions to a control box.Will therefore look like the sequential control and process control such event will select the functionalization method to carry on processing,other elephant motion control and so on can also share in the same control structure system.May believe that the PLC technology will continue to the open style control system direction to shift,particularly based on industry PC control system.The latter except,in the flexible aspect has outside the entirely different superiority compared to traditional PLC,but also has other merits, like can reduce the system to put in the market the cycle,reduces the system investment expenses, enhances from the factory first floor to the enterprise office automation data message mobile efficiency and so on.Already obtained the very good solution about the industry PC control system's real-time response question,perhaps its main thing still hid behind the technology,but lacks the corresponding track record.As for PLC,ruggedness is one of its main features,this already had the quite many track records to confirm.The industrial user still very carefully treated PLC,they are doing the different technical test work to PLC.When uses one kind of new technology,the industrial user needs to consider the question is must take the big risk,simultaneously needs to consider that can bring how many opportunities and the income to its commercial activity.But the industrial user believed not completely the open style control system brings advantage.Along with the technical further development,they start to downplay these ideological concept gradually.The industrial user is being balanced uses the risk which the new technology exists and the income which brings for theirs commercial activity,in order to will provide the effective safeguard for present's decision-making.The industry PC technology has provided many functions,can strengthen PLC the function characteristic,cooperates the processor including the Inner Tibet video frequency and the high speed floating point digit.Although Microsoft Corporation has not promoted further this function characteristic plan,but new Windows CE3.0can definitely satisfy the process control well the need.Some time ago,Siemens Corporation announced a set newly based on the open style control system's software product,namely3.0edition SIMATIC WinAC(Windows automation center). WinAC is based on Windows NT,with SIMATIC S7PLC compatible suiting in industry PC control system solution.WinAC3.0provided had the high integration rate Profibus field bus local area network's connection performance,as well as long-distance programming.In addition,it also integrated for the scene control device localization has provided one kind of new DeviceNet the I/O device driver,uses in DeviceNet which connected installs I/O equipment.The Steeplechase software company has also promoted set of supports are sturdy and healthy when process control embedded Windows the NT operating system interface unit.This part further unified Steeplechase Corporation to use the SBS technology and to move was sturdy and healthy in Windows NT environment industry Compact PCI when the control software.Now,the Steeplechase Corporation's visualization logic controller already promoted to5.0editions.This controller suits in Windows NT4.0and the Windows20,002kind of operating systems,itsreal-time engine can direct and ordinary Ethernet and TCP/IP integrates in together.5.0edition's controllers have used one kind of enlargement mode OPC server driver,thus has the quicker running rate compared to the beforehand edition.Other characteristics also include the new OI network characteristic,as well as can let industrial user design the richly colorful dynamic graph picture and so on.Transysoft Corporation had promoted the new edition ISaGRAF series industrial control configuration software package recently,namely ISaGRAF PRO,it is based on the IEC61131-3 international standards,and independence in any hardware platform soft logical automation control software package.In a network process control system environment,this software package can apply in many kinds of configurations and the distributional control system's development,it has contained a set of development kit,the application procedure working platform,as well as corresponding“hypothesized machine”when movement goal.When this movement the goal can move in various hardware platform.The CTC automation Engineering firm had already issued set of new control software package MachineLogic PCLC(industry PC logic controller),this software may let industry PC act PLC the role,and was still maintaining the industry PC function characteristic.This software can complete the control task which PLC determined,and the program time is equally quick,in1ms; Can also the simultaneous working multi-duty work,but cannot simultaneously surpass16control duties.One kind has the priority and the multitasking essence mechanism is maintaining to each control duty track,guaranteed that the control duty can obtain the highest priority.This software can move the complete5kind of IEC61131-3standard program design language and the PID control procedure,supports two types the I/O control devices.One kind is looks like Profibus and DeviceNet and so on such field bus I/O equipment;Another kind is looks like ISA and PC/104 such industry PC the I/O template.Moreover,this software has also provided to control system's online edition configuration function.The procedure may95/98and under Windows NT develops in Windows and moves,but can also carry out under RTXDOS.SoftPLC Corporation also provided one kind of labor to control software product Tealware, some people were called as very vividly this kind of software product are putting on industry PC clothes'PLC.These installed on support's control system already had the small PLC form factor, but the SoftPLC Corporation's control software was already inserted to CPU.The Tealware software can satisfy each type industrial user the need,from small,single plane system to large-scale,scattered multi-control workstation application.Its characteristic including entire series I/O module,Inner Tibet Ethernet and industry serial communication connection.Recently,Tealware the software already promoted to2.3editions.And,the control software has provided in fact the infinite trapezoidal chart logical control step the foreword,simultaneously allows to have surpasses1,000,000characters the data sheets;Many OI/SCADA application connection;The Inner Tibet Java engine and the FTP server use in the long-distance maintenance and the management;Support user compile C,C,Java procedure and device driver;Suits uses in the embedded Web server;Programming online movement pattern;Firm I/O module support ability and many other standard PLC function;May move,or is A-B Corporation's PLC-which the process which inputs transforms。
单片机 PLC 外文翻译 外文文献 英文文献 PLC在回旋加速器控制上的应用
附件3：外文文献原文PLC Application in the Control of CIAE-30 Cyclotron1 OverviewA PLC consists of a Central Processing Unit (CPU) containing anapplication program and Input and Output Interface modules, which is directly connected to the field I/O devices. The program controls the PLC so that when an input signal from an input device turns ON, the appropriate response is made. The response normally involves turning ON an output signal to some sort of output devices.In an automated system, the PLC is commonly regarded as the heart of the control system. With a control application program (stored within the PLC memory) In execution, the PLC constantly monitors the state of the system through the field input devices’ feedback signal. It will then based on the program logic to determine the course of action to be carried out at the field output devices. The PLC may be used to control a simple and repetitive task, or a few of them may be interconnected together with other host controllers or host computer through a sort of communication network, in order to integrate the control of a complex process.In general, a Control System is a collection of electronic devices and equipment which are in place to ensure the stability, accuracy and smooth transition of a process or a manufacturing activity. It takes any form and varies in scale of implementation, from a power plant toa semi-conductor machine. As a result of rapid advancement oftechnology, complicated control tasks accomplished with a highly automated control system, which may be in the field devices （such as operator panel, motors, sensors, switches, solenoid valves and etc.）, capabilities in network communication enable a big scale implementation and process co-ordination besides providing greater flexibility in realizing distributed control system. Every single component in a control system plays an important role regardless of size.A typical PLC control system consists of the hardware, softwareand network components, together with the controlled functions andassociated documentation. The PLC hardware can include a rack,power supply, CPU, network interface card, digital or analog I/O cards, and other special purpose cards such as high-speed counter, motioncontrol, pulse input and others. The software portion of a PLC controlsystem involves firmware – which is the operating system in the PLCworld, and programming software tools and application softwareusually developed by a system integrator as EID ELECTRONICS for adedicated process control. Depending on the size of target process and the operational requirements, the structures of PLC control systemcan vary. More often, a supervisory control and data acquisition system is applied, this is the HMI. Such system consists of a PLC based control on the plant level, graphic screen interface on the operation level, and processing server on the management level.2 PLC application——PLC-controlled mini-cyclotronCIAE-30 compact cyclotron is a new kind of accelerator dedicated to medical radio-isotope production. Its main features are compact structure, low power consumption, high beam intensity and easy change of energy. It consists of complex equipment, e.g. external ion source, magnet, R.F. generator, stripper, vacuum, water cooling, pneumatic activator, transportation line, beam diagnostics, targetry and various power supplies. The whole production process includesH- beam production, acceleration, electron stripping, extraction, focusing, transportation, targetcontrol, radioisotope analyses and sampling. Fig.1 shows the main body of CIAE-30 cyclotron.The control hardware consists of two parts: PLC modules and operation console. PLC modules include: three CPUs (922R), one coordinator (923C), a number of analog and logical I/Os, one communication processor (CP527), one intelligent processor(IP241), special bus and internal supplies. Operation console includes: a keyboard, a large high resolution colour monitor, two encoders, beam diagnosis and a printer. PLC communicates with the cyclotron equipment through the logical and analog I/Os, which translate orders to and receive status messages from all the different devices. The PLC communicates with the console through the communication and intelligent interfaces, which receive operator instructions and transmit the processed status signals to be displayed on the screen or printed on Fig.1PLC communicates with the cyclotron equipmentthrough the logical and analog I/Os, which translate orders to and receive status messages from all the different devices. The PLC communicates with the console through the communication and intelligent interfaces, which receive operator instructions and transmit the processed status signals to be displayed on the screen or printed on paper. All analog parameters of the cyclotron can be adjusted using the two encoders.The cyclotron status can be clearly graphically displayed on the monitor screen. These screens are called 'page's. Every page not only displays the key parts of the different systems, but also gives the real time dynamic messages by changing colour or positions. Different pages also assign different meanings to the function keys, according which the operator can choose appropriate instructions to the PLC. Fig.3 shows the page structure of the operation synopsis. Two encoders can be assigned to any of the analog parameters for tuning at any time. These parameters directly determine the cyclotron specifications, e.g. beam energy, intensity, extraction efficiency and ratio of the beam distribution among different targets. Different set of parameters can be stored into the PLC library, which is able to contain up to 50 sets and any of them can called into operation when necessary, that significantly saves machine tuning time and improves operation efficiency.The PLC can operate in two modes: full automation or half automation. In the mode of full automation, the cyclotron can automatically start-up by pushing one function key. In the mode of half automation, the PLC divides the whole sequence into different sections. At end of every section, operator interventions are required but, the operation sequence and safety interlock are also managed by the PLC. The CIAE-30 cyclotron and its PLC control system have been commissioned since 1995. More than two years of operation practice has proved that PLC application in the control of cyclotron isuser-friendly, flexible and reliable.附件2：外文文献译文PLC在回旋加速器控制上的应用1 概述可编程控制器是由里面包含有应用程序的一个中央处理单元（CPU），输入接口模块和输出接口模块，然后将它们直接连接到现场输入输出设备中。
【优质文档】plc英文参考文献-word范文 (2页)
本文部分内容来自网络，本司不为其真实性负责，如有异议请及时联系，本司将予以删除== 本文为word格式，简单修改即可使用，推荐下载！ ==plc英文参考文献a water pumping control system with a programmablelogic controller (plc) and industrial wireless modules for industrial plants—an experimental setupisa transactions, in press, corrected proof, available online 3 december XXramazan bayindir, yucel cetince《电气控制与plc》参考文献参考文献[1] 张凤珊.电气控制及可编程序控制器.2版 [m].北京: 中国轻工业出版社，XX.[2] 《工厂常用电气设备手册》编写组.工厂常用电气设备手册.2版 [m].北京: 中国电力出版社，1998.[3] 马志溪.电气工程设计 [m].北京: 机械工业出版社，XX.[4] 刘增良，刘国亭.电气工程cad [m].北京: 中国水利水电出版社，XX.[5] 齐占庆，王振臣.电气控制技术 [m].北京: 机械工业出版社，XX.[6] 史国生.电气控制与可编程控制器技术 [m].北京: 化学工业出版社，XX.[7] 郁汉琪.电气控制与可编程序控制器应用技术 [m].南京: 东南大学出版社，XX.[8] 张万忠.可编程控制器应用技术 [m].北京: 化学工业出版社，XX.[9] 王兆义.小型可编程控制器实用技术 [m].北京: 机械工业出版社，XX.[10] 三菱微型可编程控制器手册 [m].mitsubishi socio-tech，XX.[11] 吴晓君，杨向明.电气控制与可编程控制器应用 [m].北京: 中国建材工业出版社，XX.[12] 李道霖.电气控制与plc原理及应用 [m].北京: 电子工业出版社，XX.[13] s7-200 cn可编程序控制器手册 [m].西门子(中国)有限公司自动化与驱动集团，XX.[14] siemens wincc手册 [m].西门子(中国)有限公司自动化与驱动集团，XX.[15] 魏艳君.多功能屋面sp板切割机 [j].机电一体化，XX，(4)：47-48.以下文字仅用于测试排版效果, 请使用时删除！“山不在高，有仙则灵。
关于PLC英文文献(最新整理)
Security in OPERA Specification based PLC SystemsGuiomar Corral, Josep M. Selga, AgustínZaballos, David González-TarragóEnginyeria i Arquitectura La Salle-Universitat RamonLlull (URL)Barcelona-Spain{jmselga, guiomar, zaballos, dgonzalez}@Luis M. TorresDesign of Systems on Silicon (DS2) SAValencia, SpainBerthold HaberlerLinz Strom GmbhLinz, AustriaAbstract— Power Line Communication (PLC) is a broadband telecommunication technology that enables the use of the existing electricity networks for high speed data transmission purposes. European project OPERA (Open PLC European Research Alliance) is a project whose strategic objective is to push PLC technology in all the different and relevant aspects. Within this framework, security is an important aspect thatshould be taken into account and integrated into thespecifications from the very beginning. The project was scheduled in two phases with a duration of two years each. Phase1 produced a first PLC specification, including security.Phase2 produced an improved specification which was submitted to the IEEE as the OPERA PLC proposal within thecontest organized by WG P1901. The paper presents the studies related to security in the PLC access technology made within this process that led to the second security specification of OPERA. Finally, an analysis of this specification isperformed.Keywords- access technologies; PLC; communications network security;OPERA project.I. INTRODUCTIONPower Line Communication (PLC) is a broadband telecommunication technology able to use the existing electricity networks for data transmission purposes, allowing any user connected to the power grid to benefit from Information Technology based services easily. The strategic objective of project OPERA (Open PLC European Research Alliance) [1] is to push PLC technology in all the different and relevant aspects (standardization, technology improvement, installation tools and processes, telecom services, dissemination,..) so as to allow the technology to become a competitive alternative to offer broadband access service to all European citizens using the most ubiquitous infrastructure, the electrical grid, which covers not only the last mile but also in-building and in-home spaces.Security has been sometimes neglected when defining standards. In fact, the initial specifications of many existing standards in related areas such as wireless [2] have been shown to have many vulnerabilities that have had to be fixedin further specifications, not without trouble for the market. Unfortunately OPERA is not different. The specification produced in OPERA Phase1 [1][3] presented also several vulnerabilities that have been fixed in OPERA Phase2 specification [4]. The writing of this second specification by OPERA was inscribed in some way in the process created by the IEEE WG P1901 with the intention of producing an IEEE standard for PLC access and in-home networks. In fact, deliverable D27 [4] is the proposal submitted by OPERA to the IEEE within the mentioned process.The presentation of the OPERA Phase2 specification and the related security analysis are the objectives of this paper.The contents of the present paper is organized as follows. Section II introduces the security requirements to be complied by the specification; Section III succinctly describes the OPERA Phase1 specification; Section IV analyzes the level of compliance of this specification; Section V outlines the basic ideas forcreating a new specification; Section VI contains a security analysis of the new specification and, finally, there is a conclusions section.II. SECURITY REQUIREMENTSThe basic objectives of any security specification are to achieve confidentiality, integrity, mutual authentication and availability. These objectives can be threatened by a series of attacks.Confidentiality is interpreted as the privacy of transactions between two nodes from all other nodes. It is made possible by the techniques of cryptography. The most relevant known attacks against confidentiality are [5]: brute force attack, dictionary attack, eavesdropping attack and precomputation attack.Data integrity refers to ensuring that data has not been altered during the transmission process. Malicious manipulation and forging of messages are different attacks against data integrity. It can be prevented by the use of Message Integrity Checks (MIC).The function of admission control is to guarantee that network resources are only accessed by authorized devices which are who claim to be. Thus, it contains two aspects, one is authentication of the stations and the other is authorization to access the resources. Normally both functions are combined in a single access protocol. Different attacks against admission control are the following: identity usurpation, replay attacks, man-in-the-middle attacks, hijack of MAC addresses, session hijacking, masquerading, malicious device and message interception. Availability refers to the prevention from accessing and using the network by some unauthorized party. Attacks to availability are called Denial of Service (DoS) attacks. The security requirement demands that the specificationmust be robust against these attacks as well as to any other possible attack.III. SUCCINCT DESCRIPTION OF OPERA PHASE 1 SECURITY SPECIFICATION OPERA1 Specification [2][3] is aimed for PLC access networks and defines three types of devices, Head-End (HE), Repeaters (TDR, Time Division Repeaters) and Customer Premises Equipment (CPE). They typically form amulti-hop system like the one depicted in Figure 1.Confidentiality in OPERA1 is achieved by the use of DES[6] and 3DES[7] encryption systems. The admission control process involves three messages: an Access Frame that invites nodes to join the network, a contention Access Reply Frame that is an answer to the Access Frame and arequest to join the network and, finally, an Access Protocol Packet that basically informs about the success or failure of the admission control process. It is, thus, a 3-wayhandshake.The MAC layer is based on token passing controlled by the HE. The HE organizes and controls the downlink data frame for all data transmission from the HE to the CPEs. It also assigns the access duration for each CPE, which allows the uplink transmissions from the CPEs to the HE [2][8].The data frame structure used in the uplink and downlink transmissions is illustrated in Figure 2 [8]. Each frame begins with a “token announce” (TA). The TA is broadcasted in the clear over the network to inform the other stations about the upcoming transmission. The TA is followed by a number of bursts, each one addressing a specific CPE. Each burst consists of a burst header followed by several OPERA packets (basically similar to Ethernet packets). An interpacket header is inserted to separate two continuous packets or fragments of packets in a burst. The last symbol of the data frame carries a “Data Token” (DT).IV. OPERA PHASE 1 SPECIFICATION SECURITY ANALYSISThe most relevant vulnerabilities of OPERA Phase1 specification that have been detected are the following:Vulnerability 1: It uses DES [6] with a 56/64 bit key which has been reported to be breakable. It has even been phased out by FIPS (Federal Information Processing Standards). Brute force attacks as well as other attacks are feasible. Vulnerability 2: Admission control is only based on MAC addresses. Since these addresses are necessarily sent in the clear over the PLC channel, they can be supplanted. Hijacking and identity usurpation are easy to deploy.Vulnerability 3: There is no mutual authentication. There is no provision to authenticate masters. A malicious masterand man-in-the-middle attacks are possible.Vulnerability 4: The OPERA1 proposal does not contain any security Message Integrity Check (MIC) that could preserve data against tampering. Vulnerability 5: Channel Estimation MPDUs are never encrypted and include no MIC. Thus they can be manipulated to cause a DoS attack.Vulnerability 6: Another possible data integrity attack is just to change the position of different blocks in the payload. This would be unnoticed due to the independent ciphering of each block. It is a permutation attack.Vulnerability 7: It uses Diffie-Hellman algorithm without any protection against Man-in-the Middle attack. Although this may seem a big number of vulnerabilities of the OPERA Phase1 specification, the situation is common with other technologies, the most relevant of them being the early IEEE802.11 security specification [1].V. OUTLINE FOR A NEW OPERA SECURITY SPECIFICATIONUpon the view of the previous vulnerabilities it was clear that a new specification was needed and that it should provide stronger encryption,stronger integrity and a new admission control method really securing authentication and authorization.A- Stronger encryption.It can be obtained by the use of AES [9] or 3DES [7] ciphering algorithms. Neither of both has been reported to be cracked until today. For the new security specification the option chosen has been AES. The reason is that upon a careful comparison with 3DES it was clear that under many scenarios AES is less costly than 3DES. Another fact is that AES is recommended by IEEE and that it is believed to be more robust than 3DES.AES is a block cipher. To achieve confidentiality in messages of arbitrary length there are five options [10] called modes of operation. From these possible modes of operation the one chosen was the CTR mode because it can be performed in parallel (CFM and OFM modes do not allow this). Also it avoids some problems from the simpler ECB mode, it is well known and trusted (it has been used for more than 20 years) and does not raise Intellectual Property Rights (IPR) concerns as OCB does.B- Stronger integrity.From the variety of mechanisms generating a Message Integrity Check (MIC) the ones that support integrated confidentiality and integrity are specially interesting because they use one algorithm for both functions, thing that may avoid hardware and software costs. So the decision was to use AES for both functions: confidentiality and MIC generation. The chosen method to performintegrated encryption and authentication was CCM (Counter with CBCMAC) as defined in RFC 3610 [11]. CCM combines CTR mode of encryption with the CBC-MAC mode of authentication. CCM has been used and studied for a longtime and has well-understood cryptographic properties. CCM uses the same encryption key for both processes but, in conjunction with other parameters, it leads to two separated keys.The chosen values of the M and L parameters of CCM are:M = 8; indicating that the MIC is 8 octets long.L = 2; indicating that the length field is 2 octets.The length of the MIC was chosen to be 64 bits since this is the minimum length recommended by [11]. Figure 3: Construction of an Encrypted Burst The previous selections are coincident with those made in standardIEEE802.11i [12] for Wireless LANs. The main difference is that encryption and integrity are not applied over the same message. Encryption is performed over data bursts, which may contain several OPERA packets, while a MIC is generated for each OPERA packet (see Figure 3). The Burst header is authenticated but not encrypted. The OPERA packet header is authenticated and encrypted. This is done to improve efficiency in the very noisy environments typical to PLC channels. In case of error it is not necessary to retransmit the whole burst but only one packet. Another difference with [12] is that the OPERA specification does not support non robust options such as WEP or TKIP. This is possible because OPERA does not have to take into account IEEE802.11 legacy systems. C-Admission controlWith respect to admission control, the open possibilities were to define a specific protocol for OPERA or to use an existing standard. If such a standard existed it seems wiser the option to use it. Fortunately this standard exists and is IEEE 802.1X [13], an IEEE standard for port-based Network Access Control in LAN, based on the EAP (Extensible Authentication Protocol) [14], that has been adapted to be used in other environments such as wireless and which today is part of IEEE802.11i. Due to the adequacy and long time experience of thisstandard the decision was to make use of it in OPERA.IEEE 802.1X defines three entities, Supplicant, Authenticator and Authentication Sever (AS) and allows foran authentication dialog after the two opening messages (EAP-Request and EAP-Response) and before the closing message (EAP-Success or Failure). The three messages of the three-way handshake of OPERA Phase1 commented in Section III have similar functionality to the three EAP messages just mentioned. The approach taken in the new OPERA specification has been to keep the three messagesas defined in OPERA Phase1 for backwards compatibility.The Authenticator is in charge of converting betweenboth formats. The process has been represented in Figure 4. The Authenticator translates messages B and D into the corresponding Radius over EAP messages anddecapsulates/encapsulates messages C, those belonging to the authentication protocol of choice.A much major difference is that the Authenticator in IEEE802.11i is the Access Point while in OPERA can be the HE but also a Repeater.This creates the difference that in OPERA the communication between the Authenticator, when it is a Repeater, and the Authentication Server (Which can be located at the HE or beyond it) is also transmitted over the PLC channel. This fact implies the need to send the messages encrypted, protected with a MIC, with the same rules as in the dialog between Supplicant and Authenticator, and encapsulated into OPERA packets.Another difference is that the Supplicant can be a CPE or Repeater. So, aRepeater can be first a Supplicant and later Authenticator. A smaller difference is that the Access Protocol Packet may convey not only success or failure information but also indication of a failed dialog. The authentication dialog allowed by IEEE802.1X/EAP allows for the use of both shared secrets and certificates. This solves the problem of OPERA1 Phase1 of authenticating only on a MAC address basis.The new specification of OPERA is quite similar to the IEEE 802.11i and it complies with the RSNA (Robust Secure Network Association) defined in it. Nevertheless, the multihop nature of PLC, as shown in Figure 1, is a major difference with respect to wireless. In fact IEEE802.11i does not take into account the possible existence of repeaters.What the OPERA specification does, is to apply recursively the dialog between Supplicant and Authenticator.A node is first Supplicant and, once admitted into the network, may become Authenticator for another Supplicant. This creates a chain of trust among devices onto which security relies upon. What happens is that the messages sent by the Authenticator to the AS are transmitted over the PLC network and, thus, should be protected with encryption and integrity mechanisms as well as the data messages.In agreement with IEEE802.11i, OPERA Phase 2 uses the EAPOL 4-way handshake for key management. The objective of this handshake is to prove mutual knowledge of the PMK (Pairwise Master Key). But prior to this handshake, the PMK has to be transferred to the Authenticator and this again has to be done by means of the secure channel formed by the mentioned chain of trust.VI. SECURITY ANALYSIS OF THE NEW SPECIFICATIONThe new OPERA security specification is quite similar to IEEE 802.11i. Although this standard was developed to overcome vulnerabilities of previous standards, it has still potential vulnerabilities [15]. A first vulnerability is the so called rollback attack, an attack that does not seem possible in the newspecification because it does not include the WEP and TKIP options ofIEEE802.11i. The reflection attack described in the same reference is also not possible because it is not allowed for a device to have simultaneously both roles supplicant and authenticator.The previously mentioned chain of trust should not be subject of concern because there is a chain of trust from the source authority to the supplicant and chains are of limited length. Nevertheless it is reasonable to think that there would be some slight degradation of security in very long chains. Another possible source of vulnerabilities in chains could come in relation to the rerouting of messages due to failures or transient situations but we have not been able to find any.Still there remain some possible DoS attacks in layer 2. Forging of management messages is possible. The solution is to authenticate management frames but here there is atrade-off between security and efficiency. Access Request and Access Reply Frames cannot be authenticated but OPERA is not vulnerable to attacks such as flooding of requests because the access process in OPERA is completely controlled by the Authenticator. A special DoS attack for OPERA Phase1 is forging bit loading messages which in the current specification are sent unencrypted. The proposal is to also encrypt these messages.Also the DoS attacks against the 4-way handshake indicated in [15] are also worth considering. Another possible attack in PLC comes from the manipulation of the impedance of the electrical line or the line itself. This may cause lead to message deletion or, worse, message interception. The implementation of suchan attack seems difficult and requires specific topologies that do not seem to be common. In any case the attack would be a Man in the Middle attackfrom which the specification is already protected because it provides for mutual authentication. Another aspect being improved is the computation burden created by the need to change the key at every hop. One mechanism to improve this aspect is to use a single key to manage the HE and the Repeaters. Another is to define a protocol to agree a single key for transmission between pairs of CPE. VII. CONCLUSIONSThe earlier OPERA Phase1 PLC specification has been detected to be vulnerable to many known security attacks.This led to the definition of a new OPERA PLC specification able to overcome the known attacks. This new OPERA specification was submitted to the IEEE as the proposal of the OPERA consortium for the IEEE standard on PLC access systems. The proposal is based on the principles of standard IEEE802.11i. This is good for many reasons. One is compatibility with wireless in hybrid systems and devices. Another is to use known and proved standards. Nevertheless there are several differences to adapt the specification to the nature of PLC. The main ones are the following:-Instead of applying Encryption and MIC computation to the same block of data, Encryption is applied to Bursts while the MIC is appended to OPERA packets. This makes the system stronger against the very noisy PLC channels.-Admission control protocol is based on IEEE 802.1X except for three messages (Access Frame, Access Reply Frame and Access Protocol Packet) which have a different format but the same functionality.-The multihop nature of PLC is a major difference. IEEE802.11i does not take into account the possible existence of repeaters while OPERA do take them into account. It applies the dialog between Supplicant and Authenticator recursively so as to create a chain of trust among devices. Messages sent by the Authenticator to the Authentication Server may have to be transmitted over the PLC network and, in this case, they are to be protected following the same mechanisms as for the rest of messages. Finally aspects that deserve moreattention have been identified and several new vulnerabilities have been taken into account to provide ideas for a refined version of the OPERA specification. ACKNOWLEDGMENTThis work is supported by FP6 project OPERA (Open PLC European Research Alliance), and by “Enginyeria I Arquitectura La Salle”, DS2 and Linz Strom Gmbh. REFERENCES[1] OPERA Specification-Part 1-Technology-Version 1.0; 31/01/2006./_files/whitepapers/opera_wp2.pdf.. . Last access: 22/02/2010 [2] Todor Cooklev, “Wireless Communication Standards”, IEEE Standards Wireless Networks Series; IEEE, 2004.[3] OPERA Specification Part 2-System-Version 1.0, 31/01/2006./_files/whitepapers/opera_wp2.pdf. Last access: 22/02/2010. [4] OPERA Deliverable D27: OPERA Specification Version 2, 2007. . Last access: 21/02/2010[5] Jon Edney and William A. Arbaugh, “Real 802.11 Security Wi-Fi Protected Access and 802.11i”, Addison-Wesley, 2004.[6] FIPS 46-3, Data Encryption Standard (DES), October, 1999.[7] NIST SP 800-67, “Triple Data Encryption Algorithm (TDEA), including its primary component cryptographic engine, the Data Encryption Algorithm (DEA)”.[8] Le Phu Do, Halid Hrasnica and Ralf Lehnert, “Performance Evaluation of the PLC-MAC Protocol in Accordance with the OPERA Specification”. Proceedings of ISPLC07, pp 447-452, Pisa, Italy, 2007.[9] Federal Information Processing Standards Publication 197:Specification for the Advanced Encryption Standard (AES) -November 26, 2001 (FIPS-97 (2002)).[10] National Institute of Standards and Technology Special Publication 800-38A, December, 2001 Edition: Recommendation for Block Cipher Modes of Operation, Methods and Techniques.[11] IETF, Request for Comments: 3610, “Counter with CBC-MAC (CCM)”,September 2003[12] IEEE P802.11i/D10.0. Medium Access Control (MAC) Security Enhancements, Amendment 6 to IEEE Standard for Information technology – Telecommunications and information exchange between systems – Local and metropolitan area networks – Specific requirements – Part 11: Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specifications. April, 2004. [13] IEEE Standard 802.1X-2001. IEEE Standard for Local andmetropolitan area networks – Port-Based Network Access [14] IETF, Request for Comments: 3748. Extensible Authentication Protocol (EAP), June 2004.[15] Changhua He and John C Mitchell, “Security Analysis and Improvements fro IEEE 802.11i”. The 12th Annual Network and Distributed System Security Symposium (NDSS'05), pages 90-110. Feb. 2005. 4778。
plc论文参考文献(精选)
plc论文参考文献（精选）plc论文参考文献（精选）本文关键词：参考文献，精选，论文，plc plc论文参考文献（精选）本文简介：随着计算机技术、信号处理技术、控制技术、网络技术的不断发展和用户需求的不断提高，PLC的软硬件水平与规模也发生了质与量的变化，今天的PLC不再局限于逻辑控制，在运动控制、过程控制等领域也发挥着十分重要的作用。
以下是我们整理的一些plc论文参考文献，希望对你论文的写作有所帮助。
plc论文参考文plc论文参考文献（精选）本文内容：随着计算机技术、信号处理技术、控制技术、网络技术的不断发展和用户需求的不断提高，PLC的软硬件水平与规模也发生了质与量的变化，今天的PLC不再局限于逻辑控制，在运动控制、过程控制等领域也发挥着十分重要的作用。
以下是我们整理的一些plc论文参考文献，希望对你论文的写作有所帮助。
plc论文参考文献一：[1]王前进，马小平，张守田。
PLC软冗余在通风机监控系统中的应用[J].工矿自动化，2014,40（01）：93-96.[2]王云刚，陈文燕。
基于MCGS和PLC的水位自动控制系统[J].测控技术，2014,33（01）：96-98+103.[3]周石强，郭强，朱涛，刘旭东。
电气控制与PLC应用技术的分析研究[J].中华民居（下旬刊），2014（01）：199+201.[4]袁文波，洪波，尤万方，殷召生，蒋彦，温柳。
S7-PLC基于Modbus/TCP协议通信研究[J].计算机工程与设计，2014,35（02）：736-741.[5]谢劲松，梁宏斌。
五轴数控铣床软PLC控制系统的研究[J].组合机床与自动化加工技术，2014（03）：82-85.[6]李本红，陈小军。
基于PLC和触摸屏的食品包装自动化生产线控制系统设计[J].机电工程技术，2014,43（01）：9-13.[7]胡世军，张红香，张代录。
PLC应用于温度控制系统的研究[J].锻压技术，2014,39（01）：118-120.[8]刘力。
关于PLC英文文献
Security in OPERA Specification based PLC SystemsGuiomar Corral, Josep M. Selga, AgustínZaballos, David González-TarragóEnginyeria i Arquitectura La Salle-Universitat RamonLlull (URL)Barcelona-Spain{jmselga, guiomar, zaballos, dgonzalez}@Luis M. TorresDesign of Systems on Silicon (DS2) SAValencia, SpainBerthold HaberlerLinz Strom GmbhLinz, AustriaAbstract— Power Line Communication (PLC) is a broadband telecommunication technology that enables the use of the existing electricity networks for high speed data transmission purposes. European project OPERA (Open PLC European Research Alliance) is a project whose strategic objective is to push PLC technology in all the different and relevant aspects. Within this framework, security is an important aspect thatshould be taken into account and integrated into thespecifications from the very beginning. The project was scheduled in two phases with a duration of two years each. Phase1 produced a first PLC specification, including security.Phase2 produced an improved specification which was submitted to the IEEE as the OPERA PLC proposal within thecontest organized by WG P1901. The paper presents the studies related to security in the PLC access technology made within this process that led to the second security specification of OPERA. Finally, an analysis of this specification isperformed.Keywords- access technologies; PLC; communications network security;OPERA project.I. INTRODUCTIONPower Line Communication (PLC) is a broadband telecommunication technology able to use the existing electricity networks for data transmission purposes, allowing any user connected to the power grid to benefit from Information Technology based services easily. The strategic objective of project OPERA (Open PLC European Research Alliance) [1] is to push PLC technology in all the different and relevant aspects (standardization, technology improvement, installation tools and processes, telecom services, dissemination,..) so as to allow the technology to become a competitive alternative to offer broadband access service to all European citizens using the most ubiquitous infrastructure, the electrical grid, which covers not only the last mile but also in-building andin-home spaces.Security has been sometimes neglected when defining standards. In fact, the initial specifications of many existing standards in related areas such as wireless [2] have been shown to have many vulnerabilities that have had to be fixedin further specifications, not without trouble for the market. Unfortunately OPERA is not different. The specification produced in OPERA Phase1 [1][3] presented also several vulnerabilities that have been fixed in OPERA Phase2 specification [4]. The writing of this second specification by OPERA was inscribed in some way in the process created by the IEEE WG P1901 with the intention of producing an IEEE standard for PLC access and in-home networks. In fact, deliverable D27 [4] is the proposal submitted by OPERA to the IEEE within the mentioned process.The presentation of the OPERA Phase2 specification and the related security analysis are the objectives of this paper.The contents of the present paper is organized as follows. Section II introduces the security requirements to be complied by the specification; Section III succinctly describes the OPERA Phase1 specification; Section IV analyzes the level of compliance of this specification; Section V outlines the basic ideas forcreating a new specification; Section VI contains a security analysis of the new specification and, finally, there is a conclusions section.II. SECURITY REQUIREMENTSThe basic objectives of any security specification are to achieve confidentiality, integrity, mutual authentication and availability. These objectives can be threatened by a series of attacks.Confidentiality is interpreted as the privacy of transactions between two nodes from all other nodes. It is made possible by the techniques of cryptography. The most relevant known attacks against confidentiality are [5]: brute force attack, dictionary attack, eavesdropping attack and precomputation attack.Data integrity refers to ensuring that data has not been altered during the transmission process. Malicious manipulation and forging of messages are different attacks against data integrity. It can be prevented by the use of Message Integrity Checks (MIC).The function of admission control is to guarantee that network resources are only accessed by authorized devices which are who claim to be. Thus, it contains two aspects, one is authentication of the stations and the other is authorizationto access the resources. Normally both functions are combined in a single access protocol. Different attacks against admission control are the following: identity usurpation, replay attacks, man-in-the-middle attacks, hijack of MAC addresses, session hijacking, masquerading, malicious device and message interception. Availability refers to the prevention from accessing and using the network by some unauthorized party. Attacks to availability are called Denial of Service (DoS) attacks. The security requirement demands that the specificationmust be robust against these attacks as well as to any other possible attack.III. SUCCINCT DESCRIPTION OF OPERA PHASE 1 SECURITY SPECIFICATION OPERA1 Specification [2][3] is aimed for PLC access networks and defines three types of devices, Head-End (HE), Repeaters (TDR, Time Division Repeaters) and Customer Premises Equipment (CPE). They typically form a multi-hopsystem like the one depicted in Figure 1.Confidentiality in OPERA1 is achieved by the use of DES[6] and 3DES[7] encryption systems. The admission control process involves three messages: an Access Frame that invites nodes to join the network, a contention Access Reply Frame that is an answer to the Access Frame and arequest to join the network and, finally, an Access Protocol Packet that basically informs about the success or failure of the admission control process. It is, thus, a 3-wayhandshake.The MAC layer is based on token passing controlled by the HE. The HE organizes and controls the downlink data frame for all data transmission from the HE to the CPEs. It also assigns the access duration for each CPE, which allows the uplink transmissions from the CPEs to the HE [2][8].The data frame structure used in the uplink and downlink transmissions is illustrated in Figure 2 [8]. Each frame begins with a “token announce” (TA). The TA is broadcasted in the clear over the network to inform the other stations about the upcoming transmission. The TA is followed by a number of bursts, each one addressing a specific CPE. Each burst consists of a burst header followed by several OPERA packets (basically similar to Ethernet packets). An interpacket header is inserted to separate two continuous packets or fragments of packets in a burst. The last symbol of the data frame carries a “Data Token” (DT).IV. OPERA PHASE 1 SPECIFICATION SECURITY ANALYSISThe most relevant vulnerabilities of OPERA Phase1 specification that have been detected are the following:Vulnerability 1: It uses DES [6] with a 56/64 bit key which has been reported to be breakable. It has even been phased out by FIPS (Federal Information Processing Standards). Brute force attacks as well as other attacks are feasible. Vulnerability 2: Admission control is only based on MAC addresses. Since these addresses are necessarily sent in the clear over the PLC channel, they can be supplanted. Hijacking and identity usurpation are easy to deploy.Vulnerability 3: There is no mutual authentication. There is no provision to authenticate masters. A malicious masterand man-in-the-middle attacks are possible.Vulnerability 4: The OPERA1 proposal does not contain any security Message Integrity Check (MIC) that could preserve data against tampering. Vulnerability 5: Channel Estimation MPDUs are never encrypted and include no MIC. Thus they can be manipulated to cause a DoS attack.Vulnerability 6: Another possible data integrity attack is just to change the position of different blocks in the payload. This would be unnoticed due to the independent ciphering of each block. It is a permutation attack.Vulnerability 7: It uses Diffie-Hellman algorithm without any protection against Man-in-the Middle attack. Although this may seem a big number of vulnerabilities of the OPERA Phase1 specification, the situation is common with other technologies, the most relevant of them being the early IEEE802.11 security specification [1].V. OUTLINE FOR A NEW OPERA SECURITY SPECIFICATIONUpon the view of the previous vulnerabilities it was clear that a new specification was needed and that it should provide stronger encryption,stronger integrity and a new admission control method really securing authentication and authorization.A- Stronger encryption.It can be obtained by the use of AES [9] or 3DES [7] ciphering algorithms. Neither of both has been reported to be cracked until today. For the new security specification the option chosen has been AES. The reason is that upon a careful comparison with 3DES it was clear that under many scenarios AES is less costly than 3DES. Another fact is that AES is recommended by IEEE and that it is believed to be more robust than 3DES.AES is a block cipher. To achieve confidentiality in messages of arbitrary length there are five options [10] called modes of operation. From these possible modes of operation the one chosen was the CTR mode because it can be performed in parallel (CFM and OFM modes do not allow this). Also it avoids some problems from the simpler ECB mode, it is well known and trusted (it has been used for more than 20 years) and does not raise Intellectual Property Rights (IPR) concerns as OCB does.B- Stronger integrity.From the variety of mechanisms generating a Message Integrity Check (MIC) the ones that support integrated confidentiality and integrity are specially interesting because they use one algorithm for both functions, thing that may avoid hardware and software costs. So the decision was to use AES for both functions: confidentiality and MIC generation. The chosen method to performintegrated encryption and authentication was CCM (Counter with CBCMAC) as defined in RFC 3610 [11]. CCM combines CTR mode of encryption with the CBC-MAC mode of authentication. CCM has been used and studied for a long time and has well-understood cryptographic properties. CCM uses the same encryption key for both processes but, in conjunction with other parameters, it leads to two separated keys.The chosen values of the M and L parameters of CCM are:M = 8; indicating that the MIC is 8 octets long.L = 2; indicating that the length field is 2 octets.The length of the MIC was chosen to be 64 bits since this is the minimum length recommended by [11]. Figure 3: Construction of an Encrypted BurstThe previous selections are coincident with those made in standardIEEE802.11i [12] for Wireless LANs. The main difference is that encryption and integrity are not applied over the same message. Encryption is performed over data bursts, which may contain several OPERA packets, while a MIC is generated for each OPERA packet (see Figure 3). The Burst header is authenticated but not encrypted. The OPERA packet header is authenticated and encrypted. This is done to improve efficiency in the very noisy environments typical to PLC channels. In case of error it is not necessary to retransmit the whole burst but only one packet. Another difference with [12] is that the OPERA specification does not support non robust options such as WEP or TKIP. This is possible because OPERA does not have to take into account IEEE802.11 legacy systems. C-Admission controlWith respect to admission control, the open possibilities were to define a specific protocol for OPERA or to use an existing standard. If such a standard existed it seems wiser the option to use it. Fortunately this standard exists and is IEEE 802.1X [13], an IEEE standard for port-based Network Access Control in LAN, based on the EAP (Extensible Authentication Protocol) [14], that has been adapted to be used in other environments such as wireless and which today is part of IEEE802.11i. Due to the adequacy and long time experience of thisstandard the decision was to make use of it in OPERA.IEEE 802.1X defines three entities, Supplicant, Authenticator and Authentication Sever (AS) and allows foran authentication dialog after the two opening messages (EAP-Request and EAP-Response) and before the closing message (EAP-Success or Failure). The three messages of the three-way handshake of OPERA Phase1 commented in Section III have similar functionality to the three EAP messages just mentioned. The approach taken in the new OPERA specification has been to keep the three messagesas defined in OPERA Phase1 for backwards compatibility.The Authenticator is in charge of converting betweenboth formats. The process has been represented in Figure 4. The Authenticator translates messages B and D into the corresponding Radius over EAP messages anddecapsulates/encapsulates messages C, those belonging to the authentication protocol of choice.A much major difference is that the Authenticator in IEEE802.11i is the Access Point while in OPERA can be the HE but also a Repeater.This creates the difference that in OPERA the communication between the Authenticator, when it is a Repeater, and the Authentication Server (Which can be located at the HE or beyond it) is also transmitted over the PLC channel. This fact implies the need to send the messages encrypted, protected with a MIC, with the same rules as in the dialog between Supplicant and Authenticator, and encapsulated into OPERA packets.Another difference is that the Supplicant can be a CPE or Repeater. So, aRepeater can be first a Supplicant and later Authenticator. A smaller difference is that the Access Protocol Packet may convey not only success or failure information but also indication of a failed dialog. The authentication dialog allowed by IEEE802.1X/EAP allows for the use of both shared secrets and certificates. This solves the problem of OPERA1 Phase1 of authenticating only on a MAC address basis.The new specification of OPERA is quite similar to the IEEE 802.11i and it complies with the RSNA (Robust Secure Network Association) defined in it. Nevertheless, the multihop nature of PLC, as shown in Figure 1, is a major difference with respect to wireless. In fact IEEE802.11i does not take into account the possible existence of repeaters.What the OPERA specification does, is to apply recursively the dialog between Supplicant and Authenticator.A node is first Supplicant and, once admitted into the network, may become Authenticator for another Supplicant. This creates a chain of trust among devices onto which security relies upon. What happens is that the messages sent by the Authenticator to the AS are transmitted over the PLC network and, thus, should be protected with encryption and integrity mechanisms as well as the data messages.In agreement with IEEE802.11i, OPERA Phase 2 uses the EAPOL 4-way handshake for key management. The objective of this handshake is to prove mutual knowledge of the PMK (Pairwise Master Key). But prior to this handshake, the PMK has to be transferred to the Authenticator and this again has to be done by means of the secure channel formed by the mentioned chain of trust.VI. SECURITY ANALYSIS OF THE NEW SPECIFICATIONThe new OPERA security specification is quite similar to IEEE 802.11i. Although this standard was developed to overcome vulnerabilities of previous standards, it has still potential vulnerabilities [15]. A first vulnerability is the so called rollback attack, an attack that does not seem possible in the newspecification because it does not include the WEP and TKIP options ofIEEE802.11i. The reflection attack described in the same reference is also not possible because it is not allowed for a device to have simultaneously both roles supplicant and authenticator.The previously mentioned chain of trust should not be subject of concern because there is a chain of trust from the source authority to the supplicant and chains are of limited length. Nevertheless it is reasonable to think that there would be some slight degradation of security in very long chains. Another possible source of vulnerabilities in chains could come in relation to the rerouting of messages due to failures or transient situations but we have not been able to find any.Still there remain some possible DoS attacks in layer 2. Forging of management messages is possible. The solution is to authenticate management frames but here there is atrade-off between security and efficiency. Access Request and Access Reply Frames cannot be authenticated but OPERA is not vulnerable to attacks such as flooding of requests because the access process in OPERA is completely controlled by the Authenticator. A special DoS attack for OPERA Phase1 is forging bit loading messages which in the current specification are sent unencrypted. The proposal is to also encrypt these messages.Also the DoS attacks against the 4-way handshake indicated in [15] are also worth considering. Another possible attack in PLC comes from the manipulation of the impedance of the electrical line or the line itself. This may cause lead to message deletion or, worse, message interception. The implementation of suchan attack seems difficult and requires specific topologies that do not seem to be common. In any case the attack would be a Man in the Middle attackfrom which the specification is already protected because it provides for mutual authentication. Another aspect being improved is the computation burden created by the need to change the key at every hop. One mechanism to improve this aspect is to use a single key to manage the HE and the Repeaters. Another is to define a protocol to agree a single key for transmission between pairs of CPE. VII. CONCLUSIONSThe earlier OPERA Phase1 PLC specification has been detected to be vulnerable to many known security attacks.This led to the definition of a new OPERA PLC specification able to overcome the known attacks. This new OPERA specification was submitted to the IEEE as the proposal of the OPERA consortium for the IEEE standard on PLC access systems. The proposal is based on the principles of standard IEEE802.11i. This is good for many reasons. One is compatibility with wireless in hybrid systems and devices. Another is to use known and proved standards. Nevertheless there are several differences to adapt the specification to the nature of PLC. The main ones are the following:-Instead of applying Encryption and MIC computation to the same block of data, Encryption is applied to Bursts while the MIC is appended to OPERA packets. This makes the system stronger against the very noisy PLC channels.-Admission control protocol is based on IEEE 802.1X except for three messages (Access Frame, Access Reply Frame and Access Protocol Packet) which have a different format but the same functionality.-The multihop nature of PLC is a major difference. IEEE802.11i does not take into account the possible existence of repeaters while OPERA do take them into account. It applies the dialog between Supplicant and Authenticator recursively so as to create a chain of trust among devices. Messages sent by the Authenticator to the Authentication Server may have to be transmitted over the PLC network and, in this case, they are to be protected following the same mechanisms as for the rest of messages. Finally aspects that deserve moreattention have been identified and several new vulnerabilities have been taken into account to provide ideas for a refined version of the OPERA specification. ACKNOWLEDGMENTThis work is supported by FP6 project OPERA (Open PLC European Research Alliance), and by “Enginyeria I Arquitectura La Salle”, DS2 and Linz Strom Gmbh. REFERENCES[1] OPERA Specification-Part 1-Technology-Version 1.0; 31/01/2006./_files/whitepapers/opera_wp2.pdf.. . Last access: 22/02/2010 [2] Todor Cooklev, “Wireless Communication Standards”, IEEE Standards Wireless Networks Series; IEEE, 2004.[3] OPERA Specification Part 2-System-Version 1.0, 31/01/2006./_files/whitepapers/opera_wp2.pdf. Last access: 22/02/2010.[4] OPERA Deliverable D27: OPERA Specification Version 2, 2007.. Last access: 21/02/2010[5] Jon Edney and William A. Arbaugh, “Rea l 802.11 Security Wi-Fi Protected Access and 802.11i”, Addison-Wesley, 2004.[6] FIPS 46-3, Data Encryption Standard (DES), October, 1999.[7] NIST SP 800-67, “Triple Data Encryption Algorithm (TDEA), including its primary component cryptographic engine, the Data Encryption Algorithm (DEA)”.[8] Le Phu Do, Halid Hrasnica and Ralf Lehnert, “Performance Evaluation of the PLC-MAC Protocol in Accordance with the OPERA Specification”. Proceedings of ISPLC07, pp 447-452, Pisa, Italy, 2007.[9] Federal Information Processing Standards Publication 197:Specification for the Advanced Encryption Standard (AES) -November 26, 2001 (FIPS-97 (2002)).[10] National Institute of Standards and Technology Special Publication 800-38A, December, 2001 Edition: Recommendation for Block Cipher Modes of Operation, Methods and Techniques.[11] IETF, Request for Comments: 3610, “Counter with CBC-MAC (CCM)”,September 2003[12] IEEE P802.11i/D10.0. Medium Access Control (MAC) Security Enhancements, Amendment 6 to IEEE Standard for Information technology –Telecommunications and information exchange between systems – Local and metropolitan area networks – Specific requirements – Part 11: Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specifications. April, 2004. [13] IEEE Standard 802.1X-2001. IEEE Standard for Local andmetropolitan area networks – Port-Based Network Access [14] IETF, Request for Comments: 3748. Extensible Authentication Protocol (EAP), June 2004.[15] Changhua He and John C Mitchell, “Security Analysis and Improvements fro IEEE 802.11i”. The 12th Annual Network and Distributed System Security Symposium (NDSS'05), pages 90-110. Feb. 2005. 4778。
plc英文参考文献(30个最新范例)
在写作plc论文时，参考文献是必不可少的，作者在选取参考文献时，应兼顾中文文献和英文文献的比例，本文整理了几十个最新的"plc英文参考文献范例"，以供参考。
plc英文参考文献范例一：[1]LIANG Ning.Development of Automatic Sorting Device for Dried Jujube Appearance Quality Based on Machine Vision [D].Yangling:Northwest A & F University,2019.[2]ZHANG Pengpeng,ZHOU Min.Design of Handling Control System for LCD Substrate Production Line [J].Combined Machine Tool and Automatic Machining Technology,2019,（9）：111-113,123.[3]CHEN Xing.Design of the Appearance Detection System of Electrolytic Capacitor Based on Machine Vision [J].Manufacturing Technology & Machine Tools,2018,674（8）：153-157.[4]SU Chaoyang.Research and Development on Capacitor Appearance Defects Based on Image Processing Technology [D].Nanjing:Nanjing University of Aeronautics and Astronautics,2018.[5]HUANG Xinbing,LIU Xiaojuan.Design of Pneumatic Household Elevator Based on PLC Control [J].Chinese Hydraulics & Pneumatics,2019,（10）：129-134.[6]WU Hanjiang,ZHANG Fengshou,ZHANG Jiaqi.Design of Honey Pomelo Sorting System Based on PLC [J].Packaging and Food Machinery,2019,37（4）：28-30.[7]LIN Zhongxing,ZENG Xianjie,ZHANG Zongshuo.Design of Automatic Pad Printing Machine for Lamp Cap Logo Based on Pneumatic Transmission [J].Chinese Hydraulics & Pneumatics,2019,（1）：117-121.[8]LI Yingjue,WEI Kexiang.Design of Automatic Measuring Machine for Wall-thickness of Flange Parts [J].Machine Tool & Hydraulics,2019,（17）：93-97.[9]LI Jibo,HUANG Yuanzheng,XUN Jiyong.The Design of Cigarette Box Appearance Detecting System Based on Machine Vision [J].China Instrumentation,2018,（6）：68-71.[10]WANG Tao,GUO Jinliang.Design and Implementation of Robot Precise Grasp Based on Image Processing [J].Manufacturing Technology and Machine Tools,2018,（12）：47-51.[11]TAO Wencai.Design of Vision Inspection System for Mobile Shell Surface Defects [D].Shenyang:Shenyang University of Technology,2018.[12]JIA Zhenzhen,ZHANG Tao,CAO Xingqiang,et al.Design and Realization of theFood Inner Packaging Detection Device Based on the Machine Vision [J].Food & Machinery,2018,34（7）：111-114.[13]LU Minzhi,WANG Zhiwei,WANG Wei.Control System Design of Automatic Laminator Based on Machine Vision Locating [J].Machine Tool & Hydraulics,2017,45（11）：59-63.[14]ZHANG Shuzhen.PLC Control in the Implementation of Surface Defect Detection Experiment Device [D].Hefei:Hefei University of Technology,2017.[15]LIU Yunjun,LIU Jinguo,LI Yangmin.Design of Automatic Docking Gripper for Pipe Joints Based on PLC Control [J].Chinese Hydraulics & Pneumatics,2018,（9）：44-48.plc英文参考文献范例二：[16]ROMIJNDERS L N G.The development of a new segmented deepwater wave generator[C]// Fourth International Symposium on Ocean Wave Measurement and Analysis.San Francisco,US:ASCE,2002:1209-1217.DOI:10.1061/40604（273）122.[17] HMIDA U B, HAMDI U, MOUNIR S. Design of wireless power and data transmission circuits for im-Plantablc biomicrosystcm[J].Biotechnology, 2007,6（2）：153-164.[18] STRASSNER B, CHANU K. Microwave power trans-mission: historical milestones and system components[J].Proceedings of the IEEE, 2013,101（6）：1379-1396.[19]WANG Y Z,GONG W,CHI L H.Numerical simulation on oscillation-sliding-uplift rock coupled motion of caisson breakwater under wave excition [J].China Ocean Engineering,2010,24（2）：207-218.[20]NOHARA B T,YAMAMOTO I,MATSUURA M.The organized motion control of multi-directional wave maker[C]//Proceedings of 4th IEEE International Workshop on Advanced Motion Control.Mie,Japan:IEEE,1996:470-475.DOI:10.1109/AMC.1996.509294.[21] Chu Liang,Chao Libo,Ou Yang,et al.Hardware-in-the-loop simulation of traction control algorithm based on fuzzy PID[J].Energy Procedia,2012,16（3）：1685.[22]LAOUAR A,GUERZIZ A,BOUSSAHA A.Calculation of eigenvalues of Sturm-Liouville equation for simulating hydrodynamic soliton generated by a piston wave maker [J].Springer Plus,2016:1369-1385.DOI:10.1186/s40064-016-2911-0.[23]Cheded.Al-Mulla. Control of a four-level elevator system using a programmable logic controller. International Journal of Electrical Engineering Education.,2003[24]Matsushita Electric Works Ltd., Automation Control Group. FPO programming manual [EB/OL]. （2004-10-05）[2008-09-10][25]He yong yi. A Control System of Material Handling in FMS. Journal of shanghai university. Vol.1.No.1.1997[26]Ren Sheng-le. Development of PLC-based Tension Control System.Chinese Journal of Aeronautics20 （2007） 266-271[27]M. Paredes, M. Sartor, C. Masclet. An optimization process for extension spring design. Computer Methods in Applied Mechanics and Engineering. 2001, 191（8）： 783-797[28]Siemens AG.Working with STEP7 V5.2 Getting Started.2002[29]Michel Gilles.Programmabe Logic Controllers:Architecture and Application Wiley.1990.[30]G.L.Batten. Programmabe Controllers:hardware.software and ApplicationNew York:MC Graw-Hill.1994.。
关于PLC英文文献
Design of PLC Timer System Based on FPGALi Kejian, Liu Tong, Cai QizhongSchool of Electronic Information and Control EngGuangxi University of TechnologyLiuzhou Guangxi China******************;****************;**************Abstract-Aiming at the design of the small PLC timer system,based on the analysis of operational characteristics of PLC timer and the process of PLC user timer program and the data transmission requirements of PLC user program execution module and the timer, a method which applies the FPGA Parallel algorithm to designing small PLC timer system , is presented. The timer system is composed of clock generator unit, timing unit, timing control unit and the chip select circuit. While the timer runs at the speed of lms timed pulse, the operation of timer is translated into the operation of RAM memory cell which is made up of FPGA. That makes user can operate on RAM memory cell instead of the timer, and it just take up a few execution time of PLC user program. This paper introduces the theory and structure of the FPGA timer system, the state transition diagram of timer control module, the timing diagram of user program execution module operating on timer, finally take an experiment and gives analysis of the results.Keywords-PLe timer system;FPGA;dynamic in/ormation code;paralle/ operation;state transition;1. INTRODUCTIONTimer is an important soft-devices of Programmable Logic Controller (PLC) [1 ][2], which is used as the time relay of relay control system. Timer is widely used in automatic control system, such as timing sampling, timing inspection, timing scanning, etc. The implementations of timing are non-programmable hardware timing, software timing and programmable hardware timing. PLCprovides hundreds to thousands of timers [3] [4], and their timing unit typically has three kinds like 1 ms, 10ms and lOOms. If the timer were implemented all by hardware design, it would be relatively simple but would take up a lot of hardware resources. Therefore, it has great practical significance to implemented this large number of timer functions reasonably. This paper proposes a theory using the FPGA Parallel algorithm to design a small PLC timer system. This timer system is composed of clock generator unit, timing unit, timing control unit and the chip select circuit. Each timing unit is made up of 3 bit dynamic information data and 28 bit timing parameters data. Several memory cells will constitute one timing unit. While operating at the speed of 1 ms timing pulse, timer control module judges the state of the 3 bit dynamic information code of timing unit and operates the timing process. At the same time, the timer control module will scan the status of user program execution module operating timer, that makes user program execution module operates on RAM memory cell instead of the timer itself and it just take up a little the executive time of PLC user program. This paper introduces the theory and structure of the FPGA timer system, the state transition diagram of timer control module, the timing diagram of user program execution module operating on timer, finally take an experiment and gives analysis of the results.II. SYSTEM DESIGNA. The operation on timer by PLC user program execution moduleThe numbers of different types PLC timer are different and neither the types of timers. The small PLC timer has three kinds of working state. The first state is when the input conditions are not satisfied, the soft component of timer coil is in power-down state and the corresponding contact is disconnected. The second state is when the input conditions are satisfied, timer works in a timing state and the corresponding contact is disconnected. The third state is when the timing is completed, the input conditions are still satisfied and the corresponding contact is closed. The PLC timer timing value T = timing resolution factor multiple timing constant K. In programming applications, once the timer is selected, the timingresolution factor is subsequently identified as Ims, 10ms or lOOms. Figure 1 is a ladder program diagram of timer TO. Timer TO is one soft component which made up of coil and its status is "1" when power is on and "O"when power is off. When timing is completed, the soft component of timer TO is power on, its contact closes and its status becomes "1 ", when timing is not completed, the soft component of timer TO is power off, its contact breaks and its status stays "0". If the timing resolution factor of TO is 1 OOms and K is 100 then the time value T = lOOms x 100 = lOs.An example of the timing process is shown in Fig.1.When the input signal XO is connected, the coil of timer TO is driven. The timer counts the lOOms pulses, at the same time, the counting value is continually compared with the preset value. When these two values are equal, the contact of TO will be connected. The function is, once the timing coils is power on, its contacts will be closed after lOs time-delay. When the input signal XO is disconnected, the coil will be reset and power off, the counter value and the output of contact TO will both be reset immediately.B. The data transmission of PLe user program execution module and timer In order to transfer one timer data between the PLC user program execution module and timer in one time, a 32-bit data line is adopted, shown in Figure 2. the operations of User program execution module on timer are OUT Txxx, Kxxx, and the corresponding state of timer's input conditions. Txxx is the address, Kxxx is the timing data. Then the information that PLC user program execution module exports to the timer system mainly contain the timing data, the timing address, the status of soft coil and the flag status of timer(being used or not). Theinformation that the timer system exports to PLC user program execution module mainly contain the timing address, the completing status of the process of timing, the control information of message read or written, etc.Timer unit is independently addressed through the address bus and chip select signals, and processes the timing operation on selected unit address. By mapping the addresses, the timer number and the unit address are one-one correspondent. The directly mapped addresses while compiling the instructions are shown in Table I.C. The design of timer control logicAccording to the operational principle of timer, the timer system based on FPGA is designed to consists of four modules, that are clock generator unit, timing unit, timing control unit and chip select circuit [5]. The block diagram of timer system is shown in Figure 2.The clock generator unit generates required reference clock cycle Ims. elkin is the input signal from the main clock that generated by the 50MHz system frequency; elk_lms is the 1 ms periodic signal output. At each rising edge, it will trigger one counting operation on timer unit by the timer control unit.Timing control unit (Timer controller) is the core component of the whole timer design. Its main function are detecting the usage status of timer i, and the operation status of timer i and the completing status of timing. If the timer i is in process and the timing hasn't completed, this timer will be minus by I. When timing completed for the first time, the information that closing the contact is sent to the soft component area of corresponding position. When timing completed for the 2nd and even the Nth time, the information won't be sent to the soft component area of corresponding Bit processing storage unit. When timer is power off for the first time, the information that breaking the contact is sent to the soft component area of corresponding Bit processing storage unit. When timer is power off for the 2nd and even the Nth time, the information won't be sent to the soft component area of corresponding position. Timing control unit does not involve the operation of instruction decoding. The timer unit carries out the cycle counting in the Ims reference clock after the timer unit has been given an initial value. Timing control unit processes state transitions in accordance with the elkin frequency. In other words, timingcontrol unit samples I ms reference clock and complete the counting operation of the 1 ms reference clock. During the initialization process, timing control unit starts the counting operation according to the timer en signal from the host controller. During the decoding process, timing control unit pauses the counting operation according to timer Jeg signal from the host controller, and give the operating right of timer unit to the host controller, till completes the decoding of the host controller.Timing unit (Timer) is actually a 256 bytes length, 32 bits read/write RAM section with a read/write independent dual data bus. There are three kinds of PLC timer: Ims, lOms and lOOms. Assign a 32-bit length of the memory cells for each timer, the definitions of each unit are as follows:D31: Using flag bit. 1 indicates that the timer will be used in the program and 0 indicates that it won't use the timer. The flag bit is identified in the initialization module;D30: input status bit. 1 indicates that the timer is power off, 0 indicates that the timer is power of f ;D29: output status bit. 1 it indicates that the timing time of timer has reached, and the timer has output, and 0 indicates that the timing time of timer hasn't reached, it is counting and timing and the timer has no outputD28: reservationD27- DO:the initial value of timer ,which acts minus subtraction. The subtraction is set in the timing control unit.The timing unit processes counting function of timer, completes the timer's clocking function under the coordination and control of control unit. Host controller unit (Host controller) is the execution module of PLC user program, where all user programs are compiled and executed. During the execution process of the "out txx kxx" instruction, host controller unit completes the start and stop control of timer unit, and exports the timer's contact state by the operation of corresponding flag bit. The timer chip select circuit is composed of combinational logic circuit by the XOR circuit. It ensures the main controller unitand the timing control unit will not occur access violation when they are accessing timer unit. These two controllers have respective chip select signals and enable signals, cooperating with the timing unit address, can access timing unit.III. PROGRAM DESIGNProgram is compiled by hardware description language verilog[6]. First, initialize the timer that is to write the timing count initial values, which Arranged in table, to the Flash memory. If the user program does not use the timer, the timer initialization is still written in timer initial value table, and this time writes is just a default value. In the last part of the timer initialization, the timer initial data table in Flash wi\l be written to the timer unit, preparing for the operation of timing count. After the power-up initialization is completed, the host controller unit begins to decode the user program and sends a timer en signal at the same time, starts the timing control unit and begins to process the timing count operation of the timer unit. The principle flow chart is shown in Figure 3. In order to maintain the stability of state transition, the state machine uses synchronous sequential finite state machine for implementation[7][8][9]. The state machine has five states. The state transition elkin is a clock-driven signal, each state should check the input state of clk_lms. During the period of its high level effective, the state machine carries out the operation of timing and counting.SO initial state: the timing control unit does not carry out any operation, send none control signal or data, and the address bus is not occupied.S 1 state: when rst reset signal is effective, the system enters initial state. When timer en signal is effective, the system enters Sl state, sending the read enable signal and address signal of reading the timer unit.S2 status: carry out the operation of timing and counting;S3 status: write enable signal is effective. The timing time is written back to timer units;S4 status: the address pluses 1 that prepares for the next timer unit operation and returns S I state;In order to cooperate with the decoding execution of host controller unit timer instructions, the timer Jeq signal which the host controller unit sends out must be checked whether it is effective before the execution of each state or not. Only when the signal timer Jeq is effective, the timing control unit can carry out the timing counting operation of timer unit. Otherwise, enable the read and write authority of main bus and keep it until the operation of host controller iscompleted. The state diagram of execution is shown in Figure 4.Host controller compiles and executes the user program. When host controller meets "OUT Txxx, Kxxx" instructions, logical operation unit exports result to the tJesultjlag signal and latch's the tJesult fiaR, then sends out the request signal timer Jeq to timer control unit. At the same time, the timer control unit will be paused. Host controller reads the timer unit and determines whether the timer starts by the corresponding bits, shown in Figure 5.The "RST Txxx" is a timer reset instruction. When executing "RST Txxx" instruction, logical operation unit produces a t Jstjiag signal, and host controller resets the timer unit D30D29 = 00 and sets the initial value of D27- D0 and timer unit is power off.When t_result_flag signal is 0: If the timer flag bit 030 is 1, i. e. timer is power on, D30D29 = 00 is set as 10 andD27- D0 are set as the initial value, at the same time the timer is power off and is been reset. If the timer flag bit 030 is 0, i. e. timer has been power off, do nothing and compile next instruction.When t_result_flag signal is 1: If the timer flag bit D30 is 0, i. e. timer is power off, timer flag D30 is set as 0 and timeris power on. D29 is set 0 and D27- D0 are set as the initial value. The counting is completed by the time controller. If the timer flag bit D30 is 1, timer has been power on and there are two cases: if the output state flag bit D29 is 1, send out timer action status and D27-D0 are set the timer's initial value; if the flag bit D29 is 0, check whether D27 - D0 bit is 0. If D27 - D0 = 0, set D29 to 1, the timing has completed and send out timer action status. If D27 –D0≠0, set D29 to 0 and send timer original state.The design of 10ms and l00ms timer are based on 1 ms timer, just add thel0ms and l00ms count variable in the Ims timer control process. For the 10mstimer unit, execute one minus 1 operation per 10ms. For the l00ms timer unit, execute one minus 1 operation per l00ms. The counting process is the same as Ims timer counting process.IV. FUNCTIONAL SIMULATIONAccording to the timer logic design mentioned above, take five units of the timer 00H -04H. From the first address, the different address of timer ram are written into the same number as the initial value. From the first address again, follow three steps: read, minus 1 count and write to complete the minus 1 count operation of the unified unit timer and then the address plus 1. Finally, repeat the above three steps until complete the timing minus 1 operation of initial unit. In the three steps discussed above, the following time need to add to the timer _req signal simulation and the continuous counting function simulation oft_clklms. The functional simulation of 1 ms timer unit is shown in Figure 6.First 80ns, write the initial value 0000000Fh into timer_ram unit 00H - 04H. From the 80ns to the 110ns, complete the minus 1 count operation of timer unit 00H following the three steps of state 2,3, 4; from the 160ns to the 190ns, add the timer_req high level effective signal, at this moment, the minus 1 count function suspends at unit02, the address bus and data bus outputs high impedance state; after110ns, the timer_req recovers low level, then complete the minus 1 count operation of 03H and 04H; from the 280ns to the 310ns, set the t _clk 1 ms signal as low level, then the address and data buses are highimpedance state; after the 3l0ns, continue minus 1 and counting functions; from the 310ns to the 380ns, rewrite the initial value because of this is a cycle simulation. But the actual situation is that the initial value writing operation should be completed by the host controller in the initialization process. It is only forconvenience to perform cycle simulation here. The continuous minus 1 operations after 380ns meet the functional requirements.V. CONCLUSIONAiming at the operating principle of small PLC timer instruction execution, this paper brings out a method which using the FPGA parallel algorithm to design a small PLC timer system, describes the design principle of the timer system, and carries out a simulation for the designed timer system and vivificates its function. The design makes the process of PLC user program execution module operate on RAM memory cell instead of the timer, and it just take up a few execution time of PLC user program In a word, the design achieves the expected design functional requirements. The design method brings essential changes for the implementation of small PLC timer system. Moditying hardware design has become as easy as moditying software design, at the same time, the design shortens the design cycle of timer and makes debug much more easily. The most important point is that this design enhances the system's reliability and meets the current complex needs of Automatic control system. ACKNOWLEDGMENTThis research was supported by Guangxi Natural Science Foundation(No: 0991067)REFERENCES[1] Haibo Huo and Jiangbo Fan.,"Data real-time changes and display design based on Mitsubishi FX2N Series PLC software components," Yantai Normal University (Natural Science), vo122,Jan.2006, pp. 34-36.[2] Milik A and Hrynkiewicz E, "Reconfigurable Logic Conrtoller Architecture, Programming, Implementation," Programmable Devices and Systems, 2002, pp.163-168.[3] Chengyuan Fang and Zhenguo Zhang,"Plant Electrical Control Technology (third edition)," Beijing: Mechanical Industry Press ,Ju1.2006, pp. 70-94.[4] Runguang Li,Feng Ran and Meihua Xu, "PLC based RISC architecture microprocessor design," Electronics , Ju1.2005, pp. 58- 62.[5] Jinting Wang and Chunhua Xi a, "FPGA based multi-function counter design," Electronic Measurement Technology, vo1.34,Mar. 2009, pp. 151-153.[6] Yuwen Xia, "Veri log Digital System Design Tutorial,". Beijing: Beijing University of Aeronautics and Astronautics Press ,Jan. 2003, pp. 307-359.[7] Shaojian, Ping Zhang and Jili Sun, "General Radar timers Design Based on finite state machine," Electron Devices, vo1.30,Oct. 2007, pp. 1634-1637[8] M. Adamski and L. Monteiro, "From Interpreted Petri NET Specification to Reprogrammable Logic Controller Design," in Proc. IEEE International Symposium on Industrial Electronics, 2000, pp. 13-19.[9] Marian, "Rigorous Design Methodology for Reprogrammable Logic Controllers," the International Workshop on Discrete-Event System Design, 2001, pp. 258-265.。
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plc英文参考文献
a water pumping control system with a programmable
logic controller (plc) and industrial wireless modules for industrial plants —an experimental setup
isa transactions, in press, corrected proof, available online 3 december XX
ramazan bayindir, yucel cetince
《电气控制与plc》参考文献
参考文献
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