测控专业英语翻译副本

1、吉林化工学院信息与控制工程学院外文翻译学生学号：11540219 学生姓名：张忠华 专业班级：测控1102 指导教师：刘麒 职 称： 起止日期：2014.3.112014.3.17 吉 林 化 工 学 院Jilin Institute of Chemical Technology Measurement,Control and InstrumentationInstrumentation is defined as the art and science of measurement and control. Instrumentation engineers are responsible

2、for controlling a whole system like a power plant.An instrument is a device that measures and/or regulates process variables such as flow, temperature, level, or pressure. Instruments include many varied contrivances that can be as simple as valves and transmitters, and as complex as analyzers. Inst

3、ruments often comprise control systems of varied processes such as refineries, factories, and vehicles. The control of processes is one of the main branches of applied instrumentation. Instrumentation can also refer to handheld devices that measure some desired variable. Diverse handheld instrumenta

4、tion is common in laboratories, but can be found in the household as well. For example, a smoke detector is a common instrument found in most western homes. Output instrumentation includes devices such as solenoids, valves, regulators, circuit breakers, and relays. These devices control a desired ou

5、tput variable, and provide either remote or automated control capabilities. These are often referred to as final control elements when controlled remotely or by a control system.Transmitters are devices that produce an output signal, often in the form of a 420mA electrical current signal, although m

6、any other options using voltage, frequency, pressure, or ethernet are possible. This signal can be used for informational purposes, or it can be sent to a PLC, DCS, SCADA system, LabView or other type of computerized controller, where it can be interpreted into readable values and used to control ot

7、her devices and processes in the system.Control Instrumentation plays a significant role in both gathering information from the field and changing the field parameters, and as such are a key part of control loops.History In the early years of process control, process indicators and control elements

8、such as valves were monitored by an operator that walked around the unit adjusting the valves to obtain the desired temperatures, pressures, and flows. As technology evolved pneumatic controllers were invented and mounted in the field that monitored the process and controlled the valves. This reduce

9、d the amount of time process operators were needed to monitor the process. Later years the actual controllers were moved to a central room and signals were sent into the control room to monitor the process and outputs signals were sent to the final control element such as a valve to adjust the proce

10、ss as needed. These controllers and indicators were mounted on a wall called a control board. The operators stood in front of this board walking back and forth monitoring the process indicators. This again reduced the number and amount of time process operators were needed to walk around the units.

11、The basic air signal used during these years was 315 psig.In the 1970s electronic instrumentation began to be manufactured by the instrument companies. Each instrument company came out with their own standard signal for their instrumentation, 1050mA, 0.251.25V, 010V, 15V, and 420mA, causing only con

12、fusion until the 420mA was universally used as a standard electronic instrument signal for transmitters and valves. The transformation of instrumentation from mechanical pneumatic transmitters, controllers, and valves to electronic instruments reduced maintenance costs as electronic instruments were

13、 more dependable than mechanical instruments. This also increased efficiency and production due to their increase in accuracy.The next evolution of instrumentation came with the production of Distributed Control Systems (DCS). The pneumatic and electronic control rooms allowed control from a central

14、ized room, DCS systems allowed control from more than one room or control stations. These stations could be next to each other or miles away. Now a process operator could sit in front of a screen and monitor thousands of points throughout a large unit or complex.Measurement Instrumentation is usuall

15、y used for measurement. Measurement is the process or the result of determining the magnitudes of many parameters (physical values). These parameters include:（1）Chemical composition；（2）Chemical properties；（3）Properties of light； （4）Vibration； （5）Weight； （6）Voltage； （7）Inductance； （8）Capacitance； （9）

16、Resistivity； （10）Viscosity； （11）Other mechanical properties of materials；（12）Properties of ionising radiation；（13）Frequency； （14）Current；（15）Pressure, either differential or static；（16）Flow； （17）Temperature；（18）Levels of liquids；（19）Density. With the exception of a few seemingly fundamental quantum

17、constants, units of measurement are essentially arbitrary; in other words, people make them up and then agree to use them.Nothing inherent in nature dictates that an inch has to be a certain length, or that a mile is a better measure of distance than a kilometre. Over the course of human history, ho

18、wever, first for convenience and then for necessity, standards of measurement evolved so that communities would have certain common benchmarks. Laws regulating measurement were originally developed to prevent fraud in commerce. Measurement methods are often scrutinized for their validity, applicabil

19、ity, and accuracy. It is very important that the scope of the measurement method be clearly defined, and any aspect included in the scope is shown to be accurate and repeatable through validation.Measurement method validations often encompass the following considerations: （1）Accuracy and precision:

20、Demonstration of accuracy may require the creation of a reference value if none is yet available.（2）Repeatability and Reproducibility, sometimes in the form of a Gauge R&R.（3）Range, or a continuum scale over which the measurement method would be considered accurate. Example: 10N to 100N force te

21、st.（4）Measurement resolution, be it spatial, temporal, or otherwise.（5）Curve fitting, typically for linearity, which justifies interpolation between calibrated reference points.（6）Robustness, or the insensitivity to potentially subtle variables in the test environment or setup which may be difficult

22、 to control.（7）Usefulness to predict end-use characteristics and performance.（8）Measurement uncertainty. （9）Interlaboratory or round robin tests. （10）other types of measurement systems analysis.ControlIn addition to measuring field parameters, instrumentation is also responsible for providing the ab

23、ility to modify some field parameters.Modern day control engineering (also called control systems engineering) is a relatively new field of study that gained a significant attention during 20th century with the advancement in technology. It can be broadly defined as practical application of control

24、theory. Control engineering has an essential role in a wide range of control systems, from simple household washing machines to high-performance F-16 fighter aircraft.It seeks to understand physical systems, using mathematical modeling, in terms of inputs, outputs and various components with differe

25、nt behaviors; use control systems design tools to develop controllers for those systems; and implement controllers in physical systems employing available technology.A system can be mechanical, electrical, fluid, chemical, financial and even biological, and the mathematical modeling, analysis and co

26、ntroller design uses control theory in one or many of the time, frequency and complex-s domains, depending on the nature of the design problem.1Control theoryThere are two major divisions in control theory, namely, classical and modern, which have direct implications over the control engineering app

27、lications. The scope of classical control theory is limited to single-input and single-output (SISO) system design. The system analysis is carried out in time domain using differential equations, in complex-s domain with Laplace transform or in frequency domain by transforming from the complex-s dom

28、ain. All systems are assumed to be second order and single variable, and higher-order system responses and multivariable effects are ignored. A controller designed using classical theory usually requires on-site tuning due to design approximations. Yet, due to easier physical implementation of class

29、ical controller designs as compared to systems designed using modern control theory, these controllers are preferred in most industrial applications. The most common controllers designed using classical control theory are PID controllers. In contrast, modern control theory is carried out in the stat

30、e space, and can deal with multi-input and multi-output (MIMO) systems. This overcomes the limitations of classical control theory in more sophisticated design problems, such as fighter aircraft control. In modern design, a system is represented as a set of first order differential equations defined

31、 using state variables. Nonlinear, multivariable, adaptive and robust control theories come under this division. Being fairly new, modern control theory has many areas yet to be explored. Scholars like Rudolf E. Kalman and Aleksandr Lyapunov are well-known among the people who have shaped modern con

32、trol theory.2Control systemsControl engineering is the engineering discipline that focuses on the modeling of a diverse range of dynamic systems (e.g. mechanical systems) and the design of controllers that will cause these systems to behave in the desired manner. Although such controllers need not b

33、e electrical many are. And hence control engineering is often viewed as a subfield of electrical engineering. However, the falling price of microprocessors is making the actual implementation of a control system essentially trivial. As a result, focus is shifting back to the mechanical engineering d

34、iscipline, as intimate knowledge of the physical system being controlled is often desired. Electrical circuits, digital signal processors and microcontrollers can all be used to implement control systems. Control engineering has a wide range of applications from the flight and propulsion systems of

35、commercial airliners to the cruise control present in many modern automobiles. In most of the cases, control engineers utilize feedback when designing control systems. This is often accomplished using a PID controller system. For example, in an automobile with cruise control the vehicles speed

36、is continuously monitored and fed back to the system, which adjusts the motors torque accordingly. Where there is regular feedback, control theory can be used to determine how the system responds to such feedback. In practically all such systems stability is important and control theory can help ens

37、ure stability to be achieved.Although feedback is an important aspect of control engineering, control engineers may also work on the control of systems without feedback. This is known as open loop control. A classic example of open loop control is a washing machine that runs through a predetermined

38、cycle without the use of sensors.3Recent advancementOriginally, control engineering was all about continuous systems. Development of computer control tools posed a requirement of discrete control system engineering because the communications between the computer-based digital controller and the phys

39、ical system are governed by a computer clock. The equivalent to Laplace transform in the discrete domain is the z-transform. Today many of the control systems are computer controlled and they consist of both digital and analog components. Therefore, at the design stage either digital components are

40、mapped into the continuous domain and the design is carried out in the continuous domain, or analog components are mapped in to discrete domain and design is carried out there. The first of these two methods is more commonly encountered in practice because many industrial systems have many continuou

41、s systems components, including mechanical, fluid, biological and analog electrical components, with a few digital controllers.Similarly, the design technique has progressed from paper-and-ruler based manual design to computer-aided design, and now to computer-automated design (CAutoD), which has be

42、en made possible by evolutionary computation.CAutoD can be applied not just to tuning a predefined control scheme, but also to controller structure optimisation, system identification and invention of novel control systems, based purely upon a performance requirement, independent of any specific con

43、trol scheme.Instrumentation engineeringInstrumentation engineering is the engineering specialization focused on the principle and operation of measuring instruments that are used in design and configuration of automated systems in electrical, pneumatic domains etc. They typically work for industries

44、 with automated processes, such as chemical or manufacturing plants, with the goal of improving system productivity, reliability, safety, optimization, and stability. To control the parameters in a process or in a particular system, devices such as microprocessors, microcontrollers or PLCs are used,

45、 but their ultimate aim is to control the parameters of a system.Instrumentation technologistsInstrumentation technologists, technicians and mechanics specialize in troubleshooting and repairing and maintenance of instruments and instrumentation systems. This trade is so intertwined with electrician

46、s, pipefitters, power engineers, and engineering companies, that one can find him/herself in extremely diverse working situations.测量，控制和仪器仪器可定义为测量和控制的艺术和科学。仪器工程师负责控制整个系统，比如一个电厂。仪器是一种用来测量和/或调节过程变量（如流量、温度、液位或压力）的装置。仪器包括许多不同的设备，可以像阀和变送器那样简单，也可以像分析仪那样复杂。仪器通常由如精炼厂、工厂和车辆这些不同流程的控制系统组成。过程控制是实用仪器的主要分支之一。仪器也可

47、以是测量某个所需变量的手持设备。多样化的手持式仪器常见于实验室，在日常生活中也可以发现。例如：烟雾探测器是西方家庭中的一种常见仪器。输出仪器包括线圈、阀、调节器、断路器和继电器等元件。这些元件控制期望输出变量，使之实现远程或自动控制功能。在远程控制或自动控制系统中，称这些元件为终端控制元件。 变送器是产生某种输出信号的装置，通常是 420mA的电流信号，当然也可以是电压、频率、压力或以太网。这个信号可作参考之用，还可以发送到PLC、DCS、SCADA系统、LabView或其它类型的计算机控制器，这个信号被转换成可读值，用于控制系统中的其它设备和过程。控制仪器在现场信息采集和现场参数转换中都起到

48、了重要作用。这本身是控制回路的一个关键部分。在早年的过程控制中，过程指标和控制元件，如阀，是由操作员在装置周围走动通过调节阀门来监测，以获得所需的温度、压力和流量。随着技术的发展，气压式调节器发明了，并安装于监测过程和控制阀的现场。这样就减少了过程操作员监测过程所需的时间。近几年，实际控制转移到中央控制室，信号被发送到控制室来监测过程，并且输出信号被送到终端控制元件，如阀门，根据需要调节过程。这些控制器和指示器安装称为控制面板的壁面上。操作员在面板前面来回走动以监测过程指示器。这就再次减少了过程操作员在装置周围来回走动所需的时间。这几年使用的基本气压信号是3-15磅/平方英寸。20世纪70年代

49、仪器公司开始生产电子仪器。每个仪器公司为他们的仪器装置推出了自己的标准信号：如1050mA, 0.251.25V, 010V, 15V, 和420mA，这只会引起混乱，直到420mA被普遍作为变送器和阀的标准电子仪器信号。从机械气动变送器、控制器和阀的控制方式向电子仪器控制方式的转变，降低了维修成本，因为电子仪器比机械仪器更可靠。同时由于精度的提高，从而提高了工作效率和产量。伴随着分散式控制系统（DCS）的产生，仪器有了进一步的发展。气动控制和电气控制室允许来自一个集中室的控制，DCS系统允许来自多个控制台的控制。这些控制台可以是相邻的，也可以相隔千里。现在过程操作员可以坐在屏幕前监控整个装置

50、和设备的成千上万的点。（1）化学成分（2）化学性质（3）光的特性（4）振动 （5）重量（6）电压（7）电感（8）电容（9）电阻（10）粘度（11）材料的其它机械性能（12）电力辐射的性质（13）频率（14）电流（15）压力（差压或静压）（16）流量（17）温度（18）液位等（19）密度除了少数看上去代表基本法则的量子常数以外，测量的单位实质上是很主观的，换句话说，人们编制并愿意使用它就可以了。本质上没有任何内在的事物决定：一英寸必须是某一特定的长度，或者一英里较一公里是一个较好的距离度量。然而，在人类历史的过程中，首先是为了方便起见，然后因为必要，测量标准逐渐形成了以便使社会有特定的共同基准。

51、最初制定法律规范尺度就是为了防止商业欺诈。通常要审核测量方法的有效性、适用性和准确性。明确界定测量方法的使用范围是非常重要的，并且这个范围里的任何方面通过验证被证明是正确的和可复验的。测量方法的验证通常包括以下注意事项：（1）准确度和精确度。如果目前没有任何有效值，准确度的验证可能需要规定一个参考值。（2）重复性和再现性，有时是以量规“R&R”的形式表示。（3）在量程或连续的范围内，测量方法被视为是准确的。例如：10N到100N的力测试。（4）测量分辨率是空间的、时间的，或其它形式。（5）曲线拟合,通常为直线拟合，这证明标准参考点之间的插值法是正确的。（6）鲁棒性，或是对测试环境中潜在

52、的细微变量或难以控制的装置的不敏感度。（7）实用性，用来预测最终用途的特点和性能。（8）测量不确定度。（9）多个实验室进行的或循环的测试。（10测量系统分析的其它类型。除了测量现场参数，仪器还负责提供修改某些现场参数的能力。现代控制工程（也叫控制系统工程）是一个比较新的研究领域，随着科技的进步，在20世纪这个领域得到了显著的关注。它大致可以被定义为控制理论的实际应用。在广泛的控制系统中，如从简单的家用洗衣机到高性能的F-16战斗机，控制工程起着很重要的作用。控制工程根据输入、输出和不同性质的各种元件，建立数学模型，分析物理系统。使用控制系统设计工具来为这些系统开发控制器。在物理系统中运用有效的技术来执行这些控制器。系统可以是机