测控技术与仪器专业英语课文翻译单元2

Today, digital computers and other microprocessor-based devices have replaced analog recording and display technologies in all but the simplest data acquisition applications. And while computers have had an undeniably positive impact on the practice of data acquisition, they speak only a binary language of ones and zeroes.
句中but表示否定，意为“了……”，
译为：现在，数字计算机和其他基于微处理器的设备代替了所有模拟记录和显示器，唯独不能代替最简单的数据采集功能。尽管计算机技术对于数据获取工作确实有积极地影响，但它们只能显示1，0二进制代码。
Manufacturing processes and natural phenomena, however, are still by their very nature analog. That is, natural processes tend to vary smoothly over time, not discontinuously changing states from black to white, from on to off. To be meaningfully recorded or manipulated by a computer then, analog measurements such as pressure, temperature, flow rate, and position must be translated into digital representations.

译为：然而，制造过程和自然现象仍然是一种自然模拟过程。那就是说，自然过程是随着时间的推移逐渐变化的，而不是直接从白到黑，从开到关的间断变化。要使用计算机对模拟量，例如压力、温度、流速、和位置，进行有意义的记录或是控制，必须先将它们转换为相应的数字量。
Inherently digital events, too, such as the tripping（平稳地进行）of a motor or a pulse generated by a positive displacement flow meter（流量计）, must be made interpretable as a transistor-to-transistor logic (TTL) level changes in voltage（TTL电平变化”）.Hence, the origination and ongoing development of input/output (I/O) systems for converting analog and digital information about real-world is shown in Figure 2.1.

译为：一些数字事件，例如使用容积式流量计测定电机或脉冲的流畅性，也必须转化为TTL电平电压才能实现。因此，对模拟和数字信息进行转换的输入/输出 (I/O) 系统的起源和持续发展过程如图 2.1所示。

Digital I/O functionality 数字I/O功能
In contrast to analog transducers（传感器，变频器；变换器）that sense continuous variables such as pressure and temperature, many transducers provide an output that is one of two states: high or low, open or closed. A pressure might be too high or a temperature too low, triggering closure of a switch. Outputs, too, are not strictly analog-solenoid. Valves typically are opened or closed.
译为：与检测连续变量（如压力和温度）的模拟传感器相比，许多传感器只有一路输出，即高或低，开或关。压力太高或温度太低都可能会触发开关关闭。传感器输出也没有严格的电磁模拟。阀门通常是打开的或关闭的。
Many pumps and heaters are simply turned on or off. Pulse signals are a

nother form of digital I/O, with one rotation of a turbine（涡轮机） flow meter or tachometer（转速计，流速计） corresponding to a single, countable event. Digital I/O also can be used for parallel communications among plug-in expansion cards, and to generate clock and other timing signals.
译为：许多水泵和加热器被简单的开启或关闭。脉冲信号是数字I/O的另一种形式，比如涡轮流量计旋转一周或与计算单一、可数事件的转速表。数字I/O也可用于嵌入式扩展卡的并行通信，产生时钟和其他计时信号。
Already in the binary language of computers, these types of digital, or discrete, inputs and outputs (I/O) are much easier for microprocessor-based data acquisition systems to deal with than analog signals.、
译为：早在计算机二进制语言中，对基于微处理器的数据采集系统来说处理这种数字式或分立式的输入输出比处理模拟信号容易。
Similar to analog-to-digital converters used for analog I/O, digital I/O is designed to deal directly with transistor（晶体管）-to-transistor logic (TTL) level voltage changes. TTL typically sets the low voltage level(低电平)between 0 and 0.8V and the high voltage level (高电平) between 2.0 and 5.0V. Voltage levels between 0.8 and 2.0V are not allowed.
译为：与用于模拟输入输出的模拟-数字转换器相类似，数字输入输出用于直接处理TTL电平的变化。通常，TTL电平的低电压为0～0.8V，高电平为2.0～5.0V。0.8～2.0V为无效电压。
A voltage change, then, from the high range to the low range (or vice versa) represents a digital change of state from high to low, on to off, etc. And because acquiring an analog signal is more complex than acquiring a digital one, analog I/O channels also are more expensive. Hence, if digital I/O is adequate, do not bother with analog.
译为：而且，电压从高电平变为低电平代表从高到低或从开到关的信号变化。而且，由于采集模拟信号比采集数字信号复杂，所以模拟输入输出通道也比数字的较为昂贵。而且，如果数字输入输出通道足够，则无需再考虑模拟输入输出通道。
Analog signal transmission 模拟信号传输
Although the microprocessor and digital network technologies have fundamentally reinvented（重复设置，（在不知他人以发明的情况下）重复发明，彻底改造，重新使用） the ways in which today’s data acquisition systems handle data, much laboratory and manufacturing information is still communicated the “old” way, via analog electrical signals.
译为：尽管微处理器和数字网络技术已经彻底改变了如今数据采集系统处理数据的方法，但是，许多实验室和制造业任然沿用以前的方法，通过模拟电信号传递信息。
To understand the ways in which an analog signal is transmitted over a circuit, it is first

important to understand the relationships that make analog signal transmission possible.
译为：为了理解模拟型号在电路中传输的方式，首要需要了解使模拟信号传输成为可能的一些关系。
It is the fundamental relationship between voltage, current, and electrical resistance that allow either a continuously varying current or voltage to represent a continuous process variable.
此句为强调句型。
译为：是电压、电流和电阻之间的基本原理使得可以用连续变化的电流或电压来表示连续过程变量。
While charge flow is electric current, voltage is the work done in moving a unit of charge (1 coulomb) from one point to another. The unit of voltage is often called the potential difference, or the volt (V). The International System of Units (SI) unit for electrical flow is the ampere (A), defined as one coulomb per second (c/s).
译为：虽然电流是电荷的定向移动形成的，电压是单位电荷从一点移动到另一点所做的功。但是电压的单位通常称为电位差，或者是伏特。国际单位制中规定电流的单位为安培（A），定义为1库伦/秒（C/S）。
A signal source of voltage, V, will cause a current, I, to flow through a resistor of resistance, R. Ohm’s law, which was formulated by the German physicist Georg Simon Ohm (1787—1854).
译为：德国物理学家乔治.西蒙.欧姆（1787-1854）提出的欧姆定律指出：信号源的电压会在电阻中产生电流。
While most single-channel analog signal transmissions use direct current (DC) variations in current or voltage to represent a data value, frequency variations of an alternating current (AC) also can be used to communicate information.
句中direct current意为“直流”，alternating current意为“交流”。
译为：虽然大多单通道模拟信号变送器使用电压电流信号中直流信号的变化来表示数据值，但交流信号频率的变化也能用于信息传递。In the early 19th century, Jean Baptiste Joseph Fourier, a French mathematician and physicist, discovered that AC signals could be defined in terms of sine waves. A sine wave is described by three quantities: amplitude, period, and frequency. The amplitude is the peak value of the wave in either the positive or negative direction, the period is the time it takes to complete one cycle of the wave, and the frequency is the number of complete cycle of the wave per unit of time the reciprocal of the period).
译为：19世纪初，法国数学家和物理学家琼.巴蒂斯特.约瑟夫.傅立叶发现交流信号可以用正弦波来定义。正弦波通过三个量定义：振幅、周期和频率。振幅是正弦波最高点或最低点的峰值，周期是波形完成一次循环所用的时间，频率是波形在单位时间内循环出现的次数。
Digital signal transmission 数字信号传输
Industrial networks that transmit data us

ing digital signals often are an integral part of a data acquisition or process control solution. A basic understanding of the network technologies that are available for various applications is required to make the best implementation decisions that can have a profound effect on the ability to adapt to ever-changing technologies.
译为：利用数字信号传输数据的工业网络是数据采集或过程控制处理的主要部分。为了做出最好的决策，对网络技术在各种应用程序中的有效性的基本了解是必要的，因为它对适应不断变化的技术的能力有着深远的影响。
For example, the type of network(s) or network products selected for a data acquisition application can greatly affect cost/benefit evaluations for future projects. Until recently, fiber optics was an expensive option that seemed like overkill for most applications. But with the information load now likely to flow between nodes on an enterprise network, fiber looks attractive.
译为：例如，为数据采集应用程序选择的网络或网络产品可能会严重影响未来项目的成本/效益评估。直到最近，光纤对于大多数应用程序还是一个昂贵的选项，而且看起来像是大材小用。但现在企业网络上的节点之间的信息可能会溢出，光纤显得很有吸引力。
Network technologies come in a bewildering array of options, and certain segments of this technology are changing at an incredible rate. The average user might spend weeks researching the various ways to build or improve a network, just to find that once a decision is made and products are purchased, the next wave of bigger, better, faster technology is now available.
译为：令人眼花缭乱的网络技术还有许多未知的部分，这项技术中确定的部分正在改变以令人难以置信的速度进行更新。普通用户可能会花费数周时间研究各种方法来建立或改进一个网络，才发现一旦作出决定，并购买产品,下一波更大、更好、更快的技术又出现了。 A well-designed, integrated solution to data transmission will yield a competitive advantage to any industrial enterprise. Users in all aspects of a business should be able to obtain plant and business data from any physical node, local or remote.
译为：一个精心设计的集成的数据传输解决方案，将使任何工业公司都能够提升竞争优势。在企业的各个方面的用户应该能够从本地或远程的任何物理节点获得业务数据。
“Gluing” pieces of new and/or existing networks together is becoming more feasible with the use of bridging, routing, and media conversion technologies that link local area, wide area, and industrial networks together. And with Internet and wireless technologies, data transmission over large geographic areas is increasingly feasible.
译为：使用桥接、路由和媒体转换技术将新网络和（或）现有网络

拼接在一起变得更加可行。这些技术将局域网、广域网和工业网络连接在一起。伴随着互联网和无线技术的发展，跨区域的数据传输越来越可行。

Data acquisition hardware 数据采集硬件
Having acquainted with the technology of how input/output (I/O) signals are generated, conditioned, linearized, and transmitted to a host computer or controlling system, now we will look at the different kinds of data acquisition hardware that are available to help you perform all of these functions.
译为：熟悉了I/O信号如何产生，调制，线性化以及如何传送到主机或是控制系统的技术之后，现在我们将看看不同种类的数据采集硬件，它们可帮助你执行所有这些功能。
Before starting, a brief good news/bad news observation: The good news is that modern microcomputer technology has made it relatively simple to install, configure, and start up a high-performance data acquisition system.
译为：在开始之前，先了解一个简短的好/坏新闻观察： 好消息是现代微机技术已经使高性能数据采集系统的安装、 配置和启动相对简单。
Experienced users will be happy to know that many of the problems encountered a few years ago are gone. New users will never realize how difficult it once was to bring up a data acquisition system.
译为：有经验的用户会很高兴知道几年前遇到的问题不复存在了。但新用户将从来不意识到一度配置一个数据采集系统是多么的困难。
The bad news is that these same technology advances have made it even more difficult than ever to select among the many options. The hardware decisions facing a user today require a great deal of study, analysis, and consideration. Every system will work, but some are better than others for each particular application. Some things to consider:
译为：坏消息是这些相同技术的进步使得现在选择采用哪种硬件系统比以往要更难。用户选择硬件时需要做大量的研究、 分析和思考。尽管每个系统都能正常工作，但对每个特定的应用来说，一些系统比其他更好。以下是需要考虑的一些事项：
1．Connect to the Internet or an intranet?
连接到 Internet 还是 intranet？
Today, users can obtain real-time data over the Internet or an in-house intranet, using a standard browser, an Ethernet（以太网） connection or modem, and a PC or network computer (NC ).
译为：如今，用户可以使用一个标准的浏览器、 一个以太网连接或调制解调器，和 PC 或网络计算机 (NC)，通过 Internet 或内部intranet获取实时数据。

A network computer has no moving disk to store programs. Instead, it downloads various software packages in the form of “applets” to the NC when needed. This means that your real-time data can be viewed by anyone in the world (if they have the proper access). The argu

ment for using NCs is powerful. It could affect your choice of hardware.
句中applets是一种小应用程序，采用Java创建的基于HTML的程序，通过浏览器运行。
译为：网络计算机没有移动磁盘来存储程序。相反，它在需要的时候，以applets程序形式将各种软件包下载到NC上。这意味着世界上任何人都可以通过网路查看您的实时数据（如果它们具有适当的访问权限）。针对网络计算机的争论是非常激烈的。它可能会影响您对硬件的选择。
2．What PC interface? 使用什么样的电脑接口？
Virtually all objections to using PCs on the plant floor have been answered, and PCs are now performing everything from real-time control to high-speed data acquisition. One major issue to be considered is the various bus architectures available for PCs.
译为：实际上，所有反对在工厂底层使用PC机的声音都已经得到了答案，现在PC机能够执行从实时控制到高速数据采集的一切工作。一个需要考虑主要的问题是可用于PC机的各种总线体系结构。
While we will discuss the various computer buses below, you may want to explore this topic in more detail to determine the effect it may have in your application, now and in the future.
译为：尽管下面我们将讨论各种计算机总线，但你可能要探讨这一主题的更多细节，以确定它可能对您现在和未来所应用的影响。
3．Is there software support? 有软件支持吗？
Most data acquisition hardware is compatible (兼容的)with most popular industrial software, or it comes with a software package of its own. Free or not, it is a good idea to investigate the software and hardware’s capabilities.
译为：大多数数据采集硬件与大多数最受欢迎的工业软件兼容，或者它配备有自己的软件包。不管免费与否，详细调查软件和硬件的性能都是一个不错的想法。
Presentation & analysis 演示和分析
After acquiring data from various sources and translating this data into bits and bytes, then we should focus on tools available to translate data into worthwhile information. These tools are primarily programming languages and off-the-shelf software packages running under Microsoft Windows and Macintosh operating systems on personal computers.
译为：采集来自各种数据源的数据，并将此数据转换成比特和字节之后，我们关注可行的工具以便将已转化的数据转化为有价值的信息。这些工具主要是，在个人计算机上的Microsoft Windows 和 Macintosh 操作系统之下运行的编程语言和现成的软件包。
The steps required to select a data acquisition software program are:
（1）Determine the features and performance necessary to accomplish the task at hand;
（2）Determine the available resources of time, money and expertise;
（3）Select the tools to perform the task

.

选择一个数据采集软件程序所需的步骤如下：
（1）确定要完成的任务所必须的功能和性能；
（2）确定可用的时间、金钱和专门知识；
（3）选择执行的任务所需的工具。 Selection of tools requires investigation of available software programs and languages, and of operating systems under which these programs and languages will run.
译为：工具的选择需要调查可用的软件程序和语言，以及将运行这些程序和语言的操作系统。
Various versions of Microsoft Windows have come to dominate the operating system market for PC-based data acquisition systems. Many data acquisition software packages are designed to run on more than one operating system, but the Windows operating system is almost always one of the available choices.
译为：各种版本的 Microsoft Windows主宰基于 PC 的数据采集系统的操作系统市场。许多数据采集软件包都被设计成可在多个操作系统上运行，但 Windows 操作系统几乎总是可用的选项之一。
Once the operating system is selected, the next decision to be made is whether to write custom software or to buy an off-the-shelf package, and then to determine what data needs to be collected and what type of analysis and presentation is required for the data. Options range from simple plotting of an analog variable versus time to extremely sophisticated mathematical analysis of multiple analog and discrete values.
译为：一旦操作系统选定之后，下一步需要决定是编写自定义软件，还是买现成的软件包，然后确定需要收集哪些数据以及数据分析与演示文稿的类型。可选择的范围从随时间变化的模拟的变量的简单绘图到极其复杂的多个模拟和离散值的数学分析。
Data analysis techniques can be divided into three main areas: Process monitoring, Mathematical manipulation, and Statistical analysis.
译为：数据分析技术可以分为三个主要方面： 过程监控、 数学处理和统计分析。
Process monitoring （过程监控）Analog and discrete data are collected and displayed in a graphical format. Data is usually displayed on a graph versus time, or another variable.
译为：过程监控即收集模拟和离散数据并以图形的形式显示出来。数据通常显示在以时间或另一个变量为横轴的坐标图上。
Mathematical manipulation （数学变换）Data is analyzed using various high-level mathematical techniques such as fast Fourier transform (FFT)（傅里叶变换），curve fitting, filtering, etc.
数学处理即使用各种高级数学技术如快速分析数据傅里叶变换 (FFT) 曲线拟合、 过滤等进行数据分析。
Statistical analysis Data is analyzed using various statistical techniques including X-bar and R-bar charts, frequency histograms, Chi-square analysis, etc.
译为：数据分析用到的各种统计方法包括：X直

方图，R直方图，频率柱状图，卡方检验等。Recording, printing & storage（记录、印刷、存储）
Once data has been acquired, there is often a need to store it for current and future reference. Today, alternative methods of data storage embrace both digital computer memory and that old traditional standby（备用的人或物）-paper.
译为：一旦采集到数据后，往往需要将它存储起来，以备当前和未来参考。今天，数据存储的替代方法包括数字计算机内存存储和传统备用手段—纸。Covering in any detail the scores of instruments on the market today for recording, logging（把……载入正式记录，记录，把……记入航海日志 ）, printing, and storage of data is far beyond the scope of this section. The aim here is to identify and define major categories and offer the prospective user some practical guidelines to a selection best suited for the application.
译为：对今天市场上各种仪器的评分包括日志记录、打印、数据存储方面所有的细节，已经远超出本节的范围。在这里，目的是确定和定义主要的类别，并向潜在的用户提供一些实际的指引，以便其选择最适合的应用程序。
Broadly speaking, there are two principal areas where recorders or data loggers（记录器，登录器）are used:
(1)Process measurements for such variables as temperature, pressure, flow, pH, humidity; and,
(2)Scientific and engineering applications such as high-speed testing (e.g., stress/strain), statistical analyses, and other laboratory or off-line uses where a graphic or digital record of selected variables is desired.
译为：大致来说，记录机或数据记录器用于如下两个主要领域使用
（1）对一些变量如温度、压力、流量、PH值、湿度等的过程测量
(2)科学和工程应用，如高速测试 （例如应力/张力），统计分析，及其他实验室或其他需要的图形或选定变量的数字记录的离线的用途。
Although there remains a continuing role for conventional standalone recorders that still use paper and pen or printer, new technology has also made paperless, or video-graphic, recorders export data to a PC or distributed control system (DCS) workstation, in real-time or periodically for later analysis.
译为：虽然使用纸和笔或打印机的传统的独立记录方法仍然发挥着一定的作用，但新技术占有着主导的地位，包括无纸化、视频-图形、录音机实时或定期导出数据到 PC或分布式的控制系统 (DCS) 工作站供以后分析。