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Unit 1 Measurement, Control and Instrumentation Unit 1 Measurement, Control and Instrumentation Instrumentation is defined as the art and science of measurement and control. Instrumentation engineers are responsible for controlling a whole system like a power plant. 译为: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。 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. 译为: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。 Instruments 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 instrumentation 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. 译为: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。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation Output instrumentation includes devices such as solenoids, valves, regulators, circuit breakers, and relays. These devices control a desired output 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. 句中desired output variable意为“期望输出变量” ,are referred to as意为“被称为”。 全句译为: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。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation Transmitters are devices that produce an output signal, often in the form of a 420mA electrical current signal, although many 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 other devices and processes in the system. 译为:变送器是产生某种输出信号的装置,通常是 4 20mA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。 (注: SCADA:Supervisory Control And Data Acquisition)数据采集与监视 控制系统 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation 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. 句中field意为“现场”,control loops意为“控制回 路”, Play a important role “起重要作用” , as such “就这点 而论” 全句译为:控制仪器在现场信息采集和现场参数转换 中都起到了重要作用。这本身是控制回路的一个关键部分 。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation lHistory In the early years of process control, process indicators and control elements 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(气压式调节器) were invented and mounted (安装,配有)in the field that monitored the process and controlled the valves. 译为:在早期的过程控制中,过程指示器和控制元件, 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。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation This reduced 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 process as needed. 译为:这样就减少了过程操作员监测过程所需的时间 。近几年,实际控制器转移到中央控制室,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。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation These controllers and indicators were mounted on a wall called a control board. 译为:这些控制器和指示器安装在一个壁面上,称其为控 制面板。 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. The basic air signal used during these years was 315 psig( 磅/平方英寸). 译为: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。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation 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 confusion until the 420mA was universally used as a standard electronic instrument signal for transmitters and valves. come out with “发表 ,公布,展出,提出” 译为:20世纪70年代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。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation The transformation of instrumentation from mechanical pneumatic transmitters, controllers, and valves to electronic instruments reduced maintenance costs as electronic instruments were more dependable than mechanical instruments. This also increased efficiency and production due to their increase in accuracy. 句中reduced为transformation的谓语,as引导原因 状语从句。 全句译为: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。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation The next evolution of instrumentation came with the production of Distributed Control Systems (DCS). The pneumatic and electronic control rooms allowed control from a centralized 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.译为: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和设备的成千上万的 点。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation lMeasurement Instrumentation is usually 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;化学成分 (2)Chemical properties; 化学性质 (3)Properties of light; 光的特性 (4)Vibration; 振动 (5)Weight; 重量 (6)Voltage; 电压 (7)Inductance; 电感 译为:仪器通常用于测量。测量是确定一些参数(物理 值)的大小的过程或结果。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation (8)Capacitance; 电容 (9)Resistivity; 电阻 (10)Viscosity; 粘度 (11)Other mechanical properties of materials;材料的 其它机械性能 (12)Properties of ionising radiation;电力辐射的性质 (13)Frequency; 频率 (14)Current; 电流 (15)Pressure, either differential or static;压力(差压 或静压) (16)Flow; 流量 (17)Temperature;温度 (18)Levels of liquids;液位等 (19)Density. 密度 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation With the exception of a few seemingly fundamental quantum constants, units of measurement are essentially arbitrary; in other words, people make them up and then agree to use them. 句中With the exception of意为“除以外”, quantum constants意为“量子常数”。 全句译为:除了少数几个基本的量子常数以外,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。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation 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, however, first for convenience and then for necessity, standards of measurement evolved so that communities would have certain common benchmarks (基准). Laws regulating measurement were originally developed to prevent fraud (欺诈,欺骗行为;骗子) in commerce. 译为: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。最初制定法律规范尺度就是为了防止商业欺 诈。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation Measurement methods are often scrutinized(仔细检 查,详审) for their validity, applicability, 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. 译为: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。 Measurement method validations often encompass( 围绕;包围)the following considerations: 译为:测量方法的验证通常包括以下注意事项: Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation (1)Accuracy and precision: Demonstration of accuracy may require the creation of a reference value if none is yet available. 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)Repeatability and Reproducibility, sometimes in the form of a Gauge R use control systems design tools to develop controllers for those systems; and implement controllers in physical systems employing available technology. 主语it代指“control engineering”,句子中的3个并列 成分understand,use和implement为seeks to的宾语。 全句译为: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。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation A system can be mechanical, electrical, fluid, chemical, financial and even biological, and the mathematical modeling, analysis and controller design uses control theory in one or many of the time, frequency and complex-s domains, depending on the nature of the design problem. 译为:系统可以是机械、电气、流体、化工、金融,甚 至是生物,数学建模、分析和控制器的设计采用控制理论 的时间、频率和复数(s)域中的一个或多个,的取决于设 计问题的性质。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation l1Control theory There are two major divisions in control theory, namely, classical and modern, which have direct implications over the control engineering applications. The scope of classical control theory is limited to single -input and single-output (SISO) system design. 译为:控制理论中有两个重要的部分,即经典控制理 论和现代控制理论,它们对控制工程应用有着直接的影 响。经典控制理论的应用范围局限于单输入和单输出( SISO)系统设计。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation 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 domain. All systems are assumed to be second order and single variable, and higher-order system responses and multivariable effects are ignored. 译为:系统用微分方程实现时域分析,用拉氏变换实现 复数(s)域分析,或将复数域转换到频域分析。所有系 统都被假定为二阶和单变量系统,高阶系统响应和多变量 影响被忽略。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation A controller designed using classical theory usually requires on-site tuning due to design approximations. Yet, due to easier physical implementation of classical 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. 译为:由于设计的近似性,使用经典控制理论设计的控 制器通常需要现场调整。然而,由于和使用现代控制理论 设计的系统相比,经典控制器的设计具有较简单的物理实 现性,所以这些控制器是大多数工业应用中的首选。使用 经典控制理论设计的最常见的控制器是PID控制器。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation In contrast, modern control theory is carried out in the state space, and can deal with multi-input and multi- output (MIMO) systems. This overcomes the limitations of classical control theory in more sophisticated(精密的 ,尖端的) design problems, such as fighter aircraft control. In modern design, a system is represented as a set of first order differential equations defined using state variables. 译为:相比之下,现代控制理论是建立在状态空间基础 上的,并且可以处理多输入多输出(MIMO)系统。这就 克服了经典控制理论在更复杂的设计问题(如战斗机控制 )中的局限性。在现代设计中,系统表示为一组使用状态 变量描述的一阶差分方程。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation Nonlinear, multivariable, adaptive and robust(鲁棒, 健壮的) 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 control theory. 译为:非线性、多变量、自适应和鲁棒控制理论归入这 一部分(现代控制理论)。现代控制理论作为相当新的理 论,仍有许多领域有待探索。在发展现代控制理论的人当 中,像鲁道夫E,卡尔曼和亚历山大李亚普诺夫这样的学 者是众所周知的。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation l 2Control systems Control 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 be electrical many are. And hence control engineering is often viewed as a subfield of electrical engineering. 译为:控制工程是工程学科,其重点在于不同范围动态 系统(如机械系统)的建模和导致这些系统以所期望的方 式工作的控制器设计。尽管那些控制器并一定是电气的, 但大多数控制器是电气的。因此控制工程常被认为是电气 工程的子领域。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation 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 discipline, as intimate knowledge of the physical system being controlled is often desired. 译为:然而,微处理器价格的下降使得控制系统的实际 执行实质上是微不足道的。因此,重点移回机械工程学科 ,它作为受控制的物理系统联系紧密的知识,通常是可以 期望获得的。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation 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(推进) systems of commercial airliners to the cruise(巡航) control present in many modern automobiles. 译为:电路,数字信号处理器和微控制器都可以用来实 现控制系统。控制工程有着广泛的应用范围:从商用客机 的飞行和推进系统到在许多现代车辆中存在的巡航控制。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation 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 is continuously monitored and fed back to the system, which adjusts the motors torque(扭转力 ,转(力)矩)accordingly. 译为:在大多数情况下,控制工程师在设计控制系统 时利用了反馈。这通常使用PID控制器系统完成。例如 :在有巡航控制的汽车上,车辆的速度不断被监测并反 馈给相应调节电机扭矩的系统。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation 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 ensure stability to be achieved. 译为:哪里有定期反馈,控制理论就能被用于确定系统 如何响应这样的反馈。实际中,所有这类系统的稳定性是 很重要的,并且控制理论有助于确保稳定性的实现。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation 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 cycle without the use of sensors. 译为:虽然反馈是控制工程的一个重要方面,但是控制 工程师也可能从事于无反馈系统的控制。这就是开环控制 。开环控制的一个典型例子是:一台洗衣机没有使用传感 器,而是通过预先设定的周期工作。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation l 3Recent advancement Originally, 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 physical 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. 译为:本来,控制工程是所有关于连续系统的。计算机控制 工具的发展提出了离散控制系统工程的要求,因为基于计算机 的数字控制器和物理系统之间的通信是由计算机时钟控制的。 在离散域中相当于拉普拉斯变换的是z变换。现今许多控制系统 是由计算机控制的,并且它们是由数字和模拟元件组成的。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation Therefore, at the design stage either digital components are 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 continuous systems components, including mechanical, fluid, biological and analog electrical components, with a few digital controllers. 译为:因此,在设计阶段,或是数字元件被映射到连续域 ,并且在连续域中进行,或是模拟元件映射到离散域并在离 散域进行设计。这两种方法首先是在实践中较常遇到的,因 为很多工业系统有许多带有连续系统元件,包括:机械、流 体、生物和模拟电气元件,而有很少的数字控制器。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation 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 been made possible by evolutionary computation. 译为:同样的,设计技术已经从基于纸张和直尺的手 工设计发展到计算机辅助设计,如今向计算机自动设计 ( CAutoD )发展。 Unit 1 Measurement, Control and InstrumentationUnit 1 Measurement, Control and Instrumentation CAutoD can be applied not just to tuning a predefined control scheme, but also t

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