重大自动化 过程控制_process_control_中文_翻译_第一章
重大自动化过程控制_process_control_中文_翻译_第三节新
Process Control College of Automation Chongqing University1Dynamic ResponseOutline:轮廓⏹Brief Review of the Dynamic Response简要回顾动态响应⏹First Order Models for Processes一阶模型的过程⏹Seconds Order Model for Processes二阶模型过程⏹Models for Process with Dead-Time死区时间的过程模型⏹Higher Order Models and Approximation高阶模型和近似⏹Special Features of Lead-Lag Process滞后过程的特殊特色The First Order Model of a ProcessQ,C inC1V1Whereis time constantThe general form of the 1st order model一阶模型的一般形式Steady state gain稳态增益The Second Order Model of a ProcessWhereare time constantsThe general form of the 2st order modelQ,C inV 1C 1C 2V 22'''22121222()()indC dC C t C dtdtττττ+++=)(01222t bx y a dtdya dt y d a =++withWith an ≠ 0和零初始条件Analysis of the 1st Order ProcessStep responsetransfer functionConsider a step input, x(t) =Mu(t), and X(s) = M/sThe output isThe time domain function isAnalysis of the 1st Order Process Step response阶跃响应Property 1性质1y increases from 0 to a new steadystate M K, thus self-regulatingy增加从0到一个新的稳态MK,从而自我调节Analysis of the 1st Order Process Step responseProperty 2性质2Steady state gain K = y/M,The larger gain K, the moresensitive is the output to thechange in the input增益K越大，输出随输入变化就越敏感Analysis of the 1st Order Process Step responseProperty 3At t=τ, the output isy =0.632MKThe formula above can be used to estimate space timeτ上面的公式可以用来估计空间时间τAnalysis of the 1st Order ProcessStep responseThe time domain function is 时域功能Property 4The shorter the space time τ, the faster reaches the new steady state0.25, 0.5, 1, 2Analysis of the 1st Order ProcessImpulse response脉冲响应transfer function传递函数Consider an impulse input, x(t) =M (t), and X(s) = M 考虑一个脉冲输入The output is Inverse transform反变换The output increases instantaneously at time t = 0, and decays exponentially to zero.输出瞬间增加在时间t= 0，且呈指数衰减到零Analysis of the 1st Order ProcessIntegrating process: Non-self-regulating 整合过程：非自我调节a= 0Laplace transformTime domain时域Analysis of the 1st Order Process⏹Integrating process: Non-self-regulating☐With step response, the output is a ramp function阶跃响应，输出的是一个斜坡函数☐With impulse response▪The output will not return to its original steady state▪输出不会回到原来的稳定状态▪Output value is the accumulation of what is added▪输出值会累积增加⏹Example can be☐Charging a capacity充电容量☐Filling up a tank 填充的水池Example: Show that a storage tank with pumps at its inlet and outletis a integrating process 表明储罐泵在其进口和出口是一个整合过程Mass balance of a continuous flow mixed tankat constant density is :质量守恒方程，在密度不变的情况下whereq in and q are the flow rates of the inlet and outlet q in and q 是进口和出口的流动速率A is the cross-section 截面h is the liquid level 液位hExample (cont.)⏹At steady state, we can define deviation variables⏹在稳定状态下,我们可以定义偏差变量h’=h – h s, q’in =q in – q s, and q’ =q – q s⏹Mass balance becomes⏹The general solution一般解Example (cont.)⏹The transfer function⏹Step input in either q’in or q’ Leading to a ramp response, thus no steady state阶跃输入q‘in 或q’，导致斜坡响应，因此，没有稳定的状态⏹The tank will overflow, while outlet slows down ⏹容器将溢出,当出口关小Setting q’in=constant, the transfer function is⏹The tank will be drained, while outlet speeds up ⏹容器内液体将流干，当流出速度增加Example (cont.): Visualize the integrating process 可视化的积分过程 pump 泵q inqq inqNon-Self-RegulatingThe tank will overflow, while step-in occursOther Typical1st Order ProcessesE= Voltage, 电压z = Position,K’= Spring constant弹性系数,f = friction coefficient摩擦系数Other Typical 1st Order Processes An Extra Example (cont.):RC i iVccV V dtdV RC -=where τ = RC is time constant K = 1 is steady state gain x(t) = V s is the input )1(/τt s c e V V --=Charging: Discharging:τ/t s c e V V -=Other Typical 1st Order ProcessesAn Extra Example (cont.):RCi iV )1(/τt s c e V V --=Charging:Discharging:τ/t s c e V V -=Analysis of the 2nd Order ProcessCorresponding Laplace Transform相应的拉普拉斯变换Where 说明：damping ratio阻尼比natural period of oscillation自然振荡周期natural frequency固有频率Analysis of the 2nd Order Process Characteristic polynomial特征多项式The poles are 极点是：Noticing again that a stable process requires再一次注意到一个稳定的过程需要ζ>τ)0(i.e.,>Three Cases of the PolesCase 1. overdamped process 过阻尼过程In term of the two time constants 依据两个时间常数Time constant can be derived below 被推倒21ττ and 1>ζ21ττ and or,In the case of having real poles, we have 在实极点的情况下，我们有Three Cases of the PolesCase 1. overdamped process 过阻尼过程How about the forms of transfer function in term of ? 传递函数有哪种形式按照/1 and /121ττ-- 1>ζStep response in term of the time constant 阶跃响应下的时间常数τResponse is sluggish compared with underdamped or critically damped processes 响应比较缓慢与欠阻尼或临界阻尼的进程相比Three Cases of the Poles三种极点ζCase 1. overdamped process过阻尼1>可视为时间常数Three Cases of the PolesCase 3. underdamped process 欠阻尼 10<≤ζStep responseBeing rearranged as被调整为The real part determines the exponential decay, thus the amount of can be considered as the time constant 决定了指数衰减，从而可视为时间常数τζ-τζTwo conjugate poles are两个共轭极点是τζτζ21-±-j based on 基于 τζ-τζKey Features of Underdamped Process 欠阻尼过程的主要特点(2) making control system design specifications with respect to the dynamic response 制作动态响应的控制系统设计规范⑴ fitting experimental data in the measurements of natural period and damping factor ,把测量自然周期和阻尼因子拟合过后的实验数据Features Derived from the figure for:图的特征Key Features of Underdamped Process1. Overshoot超调⏹The overshoot increases as ζ becomes smaller⏹The OS becomes zero as ζ approaches 1⏹The time to reach the peak value is Peak Time峰值时间T p⏹The time to hit the final value of y(t) is Rise Time上升时间 t rKey Features of Underdamped Process2. Frequency and Period周期⏹Noting that（注意）T=2 T p⏹The unit of the frequency is radian/time频率的单位是弧度/时间 The relationship between frequency and periodKey Features of Underdamped Process3. Settling time 调节时间 T s⏹The dominant factor forcing theoscillation to decay to zero is震荡衰减到0的主导因素是：)/(t e τζ-in ⏹To settle with ±5% of the final value is T s =3/(ζ/τ)⏹±5%误差带所需要的调节时间 T=⏹To settle with ±2% of the final value is T s =4/(ζ/τ)n ω1Key Features of Underdamped Process 4. Decay Ratio 衰减率OS为超调（overshoot）⏹The decay ratio is the square of the overshoot⏹Both quantities are functions of ζ only这两个量只是ζ函数（调节时间和衰减率）Other Typical 2nd Order ProcessesE= Voltage,z = Position,K’= Spring constant,f = Friction CoefficientM = Massh = forceProcesses with Dead Time过程控制的延迟时间The time delay between the input and output in a process输入与输出的时间延迟⏹Being also called dead time or transport lag传输延迟⏹The Laplace transform of a time delay is an exponentialfunction指数函数Processes with Dead Time A Simple ExampleProcesses with Dead Time⏹The 1nd and 2nd order models have the s-domain function S域函数⏹Td是延迟时间and⏹Dealing with the exponential functions处理的指数函数⏹Estimation with Taylor series expansion泰勒级数展开估计Estimation with Padé approximation (higher accuracy) Padé逼近估计（精度更高）Processes with Dead Time⏹The 1nd order Padé approximation⏹The Denominator introduces a negative pole, probably impacting thecharacteristic polynomial of the original process介绍了负极分母,可能影响特征多项式的原工艺⏹The numerator has a positive zero, making the process unstable分子有一个积极的零,使过程不稳定⏹The 2nd order Padé approximation⏹Having two negative poles and at least one zero⏹有两个负极点和至少一个零点Processes with Dead TimeExample: Using the 1nd order Padé approximation帕德近似to plot the step response of the 1st process with dead time 使用的一介帕德近似逼近延迟时间绘制的第一过程的阶跃响应Padé approximationObservation: the approximation is acceptable at larger timescompared with the original transfer function.逼近的函数和原函数相比可以接受Processes with Dead TimeExample (cont.) Generating the required plot 生成需要的图形（MATLAB ）Pad é approximationProcesses with Dead TimeThe response of the dead time processProcesses with Dead TimeTwo plants have different intermediate variables but have the same input-output behavior!两个工厂有不同的中间变量,但有相同的投入产出的行为!Processes with Dead TimeTwo plants have different intermediate variables but have the same input-output behavior!Higher Order Process⏹All linearized higher order system can be broken down into the 1st and 2nd order units所有线性化高阶系统可以分成一阶和二阶单位⏹The complex process like two interacting tanks can be formulated in coupled differential equations复杂的过程，像两个相互作用的容器能制定耦合微分方程⏹All these problems are considered linear⏹所有这些问题都能被线性化Higher Order ProcessA series of well-mixed vessels where the volumetric flow rate, and the respective volumes are constant 一系列混合容器，其中体积流速，和各自的容量是恒定的n 1n n n c c tc τ-=-d dHigher Order Process⏹A series of well-mixed vessels (cont.)混合容器☐The steady state gain is unity in the process 在过程中稳态增益不变☐The more tanks in the series, the more sluggish is the response of the overall process 容器越多，整个响应过程的滞后越长☐Processes that are products of the 1st order functions are called as multicapacity processes 多容量过程☐If all of space time （空间时间关系）are equal, nτττ=== (21)Higher Order ProcessExample: showing how the unit step response C n (t) becomes more sluggish as n increases 显示单位阶跃响应Cn(t)随著n 增加变得更加缓慢Higher Order ProcessExample (cont.) the Matlab code for the plot 绘制图形的MATLAB 代码The response is obviously slower, as n increses The curves can be approximated by the 1st order model with dead time 这些特征曲线可近似为滞后的一阶模型3=τApproximation of Higher Order Process⏹Higher models☐Being factored into the form partial functions考虑部分函数的形式☐Time constants have a large enough difference时间常数有很大的的差异⏹The reduced-order model approximation☐Throwing away the small time scale terms☐扔掉小时间关系☐Retaining the ones with dominant poles (larger time constants)☐固定主导极点(大时间常数)。
第一章过程控制系统概述
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第1章 过程控制系统概述
图为室温自动控制系统，自动化仪表代替了人。 恒温室
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回 风
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送风
过程控制系统的定义：
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为实现对某个工艺参数的自 动控制，由相互联系、制约 的一些仪表、装置及工艺对 象、设备构成的 一个整体。
过程控制系统的主要任务 热水 是：对生产过程中的重要参数 回水 （温度、压力、流量、物位、 图2 室温自动控制系统示意图 1—热水加热器；3—控制器； 成分、湿度等）进行控制，使 2—传感变送器；4—执行器 其保持恒定或按一定规律变化。
2．控制方案丰富
生产工业的特点、被控过程的多样性决定控制方案的多样性。系统硬件和控 制算法、软件设计。
3．控制对象大多属于慢过程
连续工业过程大惯性和大滞后的特点决定了被控过程为慢过程。
4．大多数工艺要求定值控制
被控参数的设定值为一个定值，减小或消除外界干扰，使被控量尽量保持接 近或等于设定值。
5．大多使用标准化的检测、控制仪表及装置
兰州理工大学电信学院
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第1章 过程控制系统概述
1.开环控制系统 开环控制系统(open-loop control system)是指被控对象的输出(被控 制量)对控制器(controller)的输出没有影响。在这种控制系统中，不依赖 将被控量反送回来以形成任何闭环回路。 2.闭环控制系统 闭环控制系统(closed-loop control system)的特点是系统被控对象的 输出(被控制量)会反送回来影响控制器的输出，形成一个或多个闭环。闭环 控制系统有正反馈和负反馈，若反馈信号与系统给定值信号相反，则称为负 反馈( Negative Feedback)，若极性相同，则称为正反馈，一般闭环控制系 统均采用负反馈，又称负反馈控制系统。error)描述，它表示系统输出稳态 值与期望值之差﹔快是指控制系统响应的快速性，通常用上升时间来定量描 述。 闭环控制系统的例子很多。比如人就是一个具有负反馈的闭环控制系 统，眼睛便是传感器，充当反馈，人体系统能通过不断的修正最后作出各种 正确的动作。如果没有眼睛，就没有了反馈回路，也就成了一个开环控制系 统。 3 .阶跃响应 阶跃响应是指将一个阶跃输入（step function）加到系统上时，系统 的输出。稳态误差是指系统的响应进入稳态后﹐系统的期望输出与实际输出 之差。控制系统的性能可以用稳、准、快三个字来描述。稳是指系统的稳定 性(stability)，一个系统要能正常工作，首先必须是稳定的，从阶跃响应 上看应该是收敛的﹔准是指控制系统的准确性、控制精度，通常用稳态误差 来(Steady-state)
自动化专业英语(翻译)P4U1教学课件
P4UIA A Process Control System
第四部分第一单元课文A
过程控制系统
5. 参考译文
A 过程控制系统
此部分的主要目的是满足读者对自动过程控制的需要和激励 读者来学习。自动过程控制与持续过程变量、温度、压力、流量、 成分和期望操作值一类的量有关。正如我们在后续的章节中所看 到的，过程本身是动态的。变化不断发生，并且如果激励未加入， 重要的过程变量——与安全有关的变量、产品质量和生产率—— 将不能获得期望值。 为了强化概念，让我们来考虑一个过程流通过浓缩流加热的 热变换器，其过程框图如图4-1A-1
I P
FY 10
图4-1B-1 I/P 传感器
P4UIB Fundamentals of Process Control
第四部分第一单元课文B
过程控制的基本要素
输入信号在4到20毫安之间，输出信号在3到15表压之间。其他 传感器还有：气动-电流传感器（P/I），电压-气动传感器 （E/P），气动-电压传感器（P/E）等等。
P4UIA A Process Control System
第四部分第一单元课文A
过程控制系统
① ② ③
测量（M ）：传感器和热偶电阻的组合元件经常测量被控变量。 设定（D ）：基于测量值，控制器决定怎样维持变量在期望值。 执行（A ）：作为控制器决定后的结果，系统必须采取一定的 措施，通常有终端控制元件完成。 如上所述，在每一个控制系统中这三个基本操作：M、D 和A都会存在。在某些系统中，决定-执行操作相当简单，而在 另一些系统中操作很复杂。工程人员设计控制系统时必须确保 采取的措施要影响控制变量，也就是说，采取的措施要影响测 量值。否则，系统是不可控的且有可能弊大于利。
过程控制系统第一章
锅筒
FT
开环控制的优点：
控制及时，对较频繁的主要扰
动起到补偿效果。 缺点：仅在蒸汽扰动信号对液 位有影响时，才进行补偿，对 其他影响液位的扰动无控制作 用，不能保证液位无误差。
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FFC
省煤器
给水
开环的液位控制系统
1.2 过程控制系统简介—控制系统的组成
比较机构：比较设定值 根据偏差的正负、大小 接收控制器的输出，相 与测量值并输出其差值 及变化情况，按预定规 应地改变操纵变量 扰动 f(t) 律给出控制作用 控制器
息称为输出信号。上一环节的输出信号就是下一环节的输入信号。
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控制理论的发展过程
复杂的工业过程难于推广现 代控制理论
大系统理论 主要方法：现代控制理论与系统理论相结合
无法广泛应用于工业过程控 制
智能控制 主要方法：人工智能（专家系统；模糊控制；人工神经网 络控制）与自动控制的结合
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1.1 控制理论与过程控制系统的发展状况
过程控制发展概况
• 20世纪40年代前后，处于手动状态，从50年代前后开 始，划分为如下几个阶段： • 50年代前后——第一阶段，实现了仪表和局部自动化， 主要特点： (1) 仪表为气动式，普遍采用基地式仪表和部分单元组 合仪表； （2）单输入单输出系统； （3）被控参数主要是温度、压力、流量、液位； （4）控制的目的是保证参数稳定，消除或减小扰动； （5）控制理论：频率法和根轨迹法。
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智能交通物联网
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1.2 过程控制系统简介
请描述一下驾驶员如何驾驶汽车？
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1.2 过程控制系统简介
• 请描述一下家庭热水器如何工作？
温度调节装置
控制器
加热棒
过程控制第1章_绪论
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§1-3 方块图与流程图
反馈： 闭环控制系统中，输出变量（或信号）沿着回路中的 信号流动方向总会返回到系统的输入端，与给定值进 行比较。这种把系统（或方块）的输出信号引回到系 统输入端的做法叫做反馈。
若反馈信号（被控变量测量值z）与给定值信号的方 向相反，即反馈信号z 取负值，则叫做负反馈。 测量信号与给定值信号方向相同，则叫做正反馈。 闭环控制系统是靠负反馈来达到控制的目的。 例：储槽液位控制系统；炉温控制系统
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一、生产过程及其特点 连续生产过程主要有以下几种形式： 1 ．传热过程 通过冷热物流之间的热量传递，达到控制介质温 度、改变介质相态或回收热量的目的。典型设备：换 热器 2 ．燃烧过程 通过燃料与空气混合后燃烧为生产过程提供动力 和热源。典型设备：加热炉
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一、生产过程及其特点 3 ．化学过程 由两种或几种物料化合成一种或多种更有价值的 产品的反应过程。典型设备：反应器
按被控变量的名称分类 温度，压力，流量，液位，成分等控制系统
按被控变量的数量分类 单变量控制系统，多变量控制系统
按控制器的控制规律分类 比例P控制系统，比例积分PI控制系统，比例微积分PID 控制系统 按控制系统的结构分类 反馈控制系统，前馈控制系统，前馈-反馈控制系统，
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二、过程控制系统的分类
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§1-3 方块图与流程图
图1-7 液体贮槽的工艺控制流程图
图中所示，工艺控制流程图主要是由工艺设备、 管道、元件以及构成控制系统的仪表符号及信号线等 图形符号组成。
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§1-3 方块图与流程图 仪表图形符号： 仪表图形符号可用来表达工业自动化仪表所 处理的被测变量和功能，还可以表示仪表或元件 的名称。 仪表图形符号是直径为12mm的细实圆圈， 并在其中标有仪表位号。 仪表位号由字母代号和数字编号组成，如下例所示：
自动化专业英语第三版王树青第一章翻译
自动化专业英语第三版1.1 介绍过程控制1.近年来，对过程系统的性能改善需求变得越来越困难. 更为激烈的竞争，更加严格的环境和安全规范，以及快速变化的经济条件都是加强工厂产品质量规范的关键因素2.更为复杂的情况是，由于现代制造业朝着规模更大,集成度更高的方向发展,而使不同的加工环节之间的协调能力更低, 所以加工过程更难控制.在这种工厂中，要想让一个生产环节出现的问题不对其相连的另一个生产环节产生影响,几乎是不可能的.3.近年来，考虑到工业制造逐渐加强的安全、高效需求，过程控制这个课题变得越来越受重视.实际上，对于大多数现代工业，要满足安全、高效，产品质量的要求，没有控制系统是不可能的.1.1.1说明性的例子1.图1.1.1 所示的连续加热搅拌器可以作为过程控制的典型例子.输入液态流体的质量流量率为w，温度为Ti. 槽内成分搅拌均匀，并且用电加热器，功率为Q瓦特.2.假设输入和输出流量率是相等的，并且液体密度保持恒定，也就是说温度变化足够小，密度对温度的影响可以忽略不计. 在这些条件下，槽内液体的体积保持恒定3.加热搅拌器的控制目标是保持输出温度T在一个恒定参考值TR上.参考值在控制术语中指的是给定值. 下面我们考虑两个问题.把加热搅拌器内的液体从输入温度Ti加热到输出温度TR，需要多少热量？1.要确定达到设计运行条件下的热量需求，我们需要写下槽内液体的稳定能量平衡式.在写平衡式之前，假设槽内是完美搅拌的，同时忽略热损耗.2.在这些条件下，槽内成分的温度保持一致，因此，输出温度等于槽内液体温度..3.Ti, T, w, 和QC 是液体的比热. 我们假设C是恒定的. 在设计条件下，. 将其代入方程（1），1.方程（2）是加热器的设计方程.如果我们的假设是正确的，同时输入流量和输入温度等于他们的标定值，那么有方程（2）给出的输入热量将使输出温度保持在期望值TR.但是，如果给定条件变化，会产生什么样的结果呢？这给我们带来第二个问题：2.问题2. 假设输入温度Ti随时间变化. 我们如何确保温度T保持或靠近给定值TR？最为一个特殊的例子，假设Ti增加到一个大于的值. 如果Q保持在标定值上恒定，我们可以得到输出温度将增加，因此T>TR.为应付这种情况，有一些可能的策略控制出口温度T方法1。
process control 1
WHY IS CONTROL POSSIBLE? Control is possible only if the engineer provides the required equipment during process design. Part 1: Control equipment
Communication Final element
Every engineer needs basic knowledge about control. Many exciting career opportunities exist for a technical specialist.
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WHY NOW FOR THE CONTROL COURSE?
Desired value
CONTROLLER FINAL ELEMENT PROCESS Inputs Outputs
SENSOR
What is the meaning of the arrows?
How do we select the sensor location?
WHAT DOES A FEEDBACK SYSTEM DO?
WHERE IS CONTROL DONE?
Central control room
Sensors, local indicators, and valves in the process
Displays of variables, calculations, and commands to valves are in the centralized control center. Shows a modern, computerbased control panel
重大自动化过程控制_process_control_中文_翻译_第一章
重⼤⾃动化过程控制_process_control_中⽂_翻译_第⼀章Process Control Systems过程控制系统College of Automation,Chongqing University过程控制⾃动化重庆⼤学1Outline of the IntroductionW hat Is Process Control?DefinitionA few examples and forms⼀些例⼦和形式W hat Does It Do?Differences from automatic control theory⾃动控制理论的差异?W hat to be controlled?How Does It Do?如何实现Formulating the problem制定问题Control Equipment and Process Equipment控制设备和⼯艺设备?M odeling the process of the Problem建模过程的问题Introduction to Process Control Operator’s View of Process Control操作员的观点的过程控制A Day in aLife of a PlantOperatorDefinitionThe technology ofcontrolling a series of events to transform a material into a desired end product is called process control.控制技术的⼀系列事件把资料达到所希望的最终产品,被称为过程控制Short examples:M aking of fire for cooking rice (primitive and modern)The fly-ball governor for steam engine control (1774)短的例⼦:让⽕煮⽶饭(原始的和现代)州长的fly-ball蒸汽发动机控制(1774)Tendency of industrial process controlbeing computerized,being automatized , andbeing instrumented w ith smart sensors and M EM S⼯业过程控制的趋势在计算机化,在潜意识中⾃动使⽤,被装备智能传感器和微机电系统(M EM S)A Few Examples1.Flow Control in Oil refinery Plant:Do w e run around the plant to adjust the valves w hen required?流量控制,是炼油⼚植物:我们到处跑植物调节阀门在需要的时候吗?A Few Examples2. pH ControlManual⼿册AutomatedpH controlA Few Examples:3. Room temperature controlA Few Example4. Watt Centralfugal Speed Governor ⽡特Centralfugal调速器A Few Examples5. Level Control液位控制A Few Examples6. Cross Direction ProceControl⼗字⽅向过程控制Several hundred sensors andactuators,M illisecond operation,Controlling paper thickness tow ithin microns!⼏百传感器和执⾏器,微操作,控制纸张厚度和在微⽶!A Few Examples7. Discrete M anufacturing Processes 离散型制造过程A Few Examples8. Typical continuous processes典型的连续过程A Few Examples9. Typical non-continuous processesA Few Examples10. A Semi-Continuous Process半连续过程How large shouldthe tank volume be?油箱体积是多⼤呢？Sample-Plant: M ill W ide Process Control轧机⼴泛的过程控制Sample Softw are: Honeyw ell Intellimap样品软件:霍尼韦尔IntellimapW hat Is Process Control?Summary of the Examples- Forms总结的例⼦-形式Discrete M anufacturing, M otion, and Packaging离散型制造、运动、和包装Robotic Assembly Line in Automotive Production机械的汽车⽣产流⽔线M etal Stamping for the discrete pieces of product 五⾦冲压为离散件产品Continuous Production of Fuels, Chemicals连续⽣产的燃料、化学品Room Temperature Control室温控制Nucleus Chemical Reactor核化学反应器Batch Production of intermediate/end products批量⽣产中间/终端产品Adhesives and gluesFood, Beverages, andM edicineW hat Is Process Control?Tedency: Being Compueterized, Automatized, and Instrumented by smart sensors and M EM S计算机化，⾃动化，和动态化由智能传感器和微机电系统Sensors, local indicators,and valves in the process传感器、当地的指标,和阀门在这个过程中Valve openingdetermined by thesignal from computerDisplays of variables, calculations, commands to valves andhistorical data are in the centralized control center.显⽰变量的影响,计算,命令对阀门和历史数据是在中央控制中⼼Differences from Automatic Control Theory⾃动控制理论的差异?Using Control Theory as a ToolSolving the Real-W orld Problems forM aintaining controlled variables at the desired values保持控制变量在期望值M anufacturing products w ith consistent quality w hen raw material properties change⽣产质量稳定的产品，原料性质改变时？Responding dangerous situations w ith given time危险的情况下和给定的时间响应Being Specialized by transducer作为专业的传感器Smart sensorsM EM S 微机电系统。
自动化专业英语
自动化专业英语自动化专业英语是指在自动化工程领域中使用的英语词汇和表达方式。
自动化工程是一门综合性的学科，涉及到机械、电子、计算机等多个领域的知识。
因此，掌握自动化专业英语对于从事自动化工程的专业人士来说至关重要。
本文将介绍自动化专业英语的基本词汇、常用表达和相关领域的专业术语，以匡助读者更好地理解和运用自动化专业英语。
一、基本词汇1. Automation 自动化Automation refers to the use of technology to perform tasks with minimal human intervention. It involves the use of machines, computers, and control systems to operate and control various processes.2. Control 控制Control refers to the regulation or management of a system or process. In the context of automation, control involves monitoring and adjusting the parameters of a system to achieve desired outcomes.3. Robotics 机器人技术Robotics is a branch of automation that deals with the design, construction, and operation of robots. It involves the use of mechanical, electrical, and computer engineering principles to create intelligent machines capable of performing tasks autonomously.4. Sensors 传感器Sensors are devices that detect and respond to physical or environmental changes. In automation, sensors are used to monitor various parameters such as temperature, pressure, and motion, and provide feedback to the control system.5. Programmable Logic Controller (PLC) 可编程逻辑控制器A PLC is a digital computer used for automation of industrial processes. It is designed to control machinery and equipment in real-time, based on input from sensors and programmed instructions.6. Human-Machine Interface (HMI) 人机界面HMI refers to the interface between humans and machines. It allows users to interact with and control automated systems through graphical displays, touchscreens, and other input devices.7. Industrial Internet of Things (IIoT) 工业物联网IIoT refers to the network of physical devices, sensors, and software used in industrial settings to collect and exchange data. It enables the integration of automation systems with data analytics and cloud computing, leading to improved efficiency and productivity.二、常用表达1. System integration 系统集成System integration involves combining different subsystems and components to create a unified and functional system. It requires the coordination of hardware, software, and communication protocols to ensure seamless operation.2. Process optimization 过程优化Process optimization refers to the improvement of a system or process to achieve better performance, efficiency, and quality. It involves analyzing data, identifying bottlenecks, and implementing changes to maximize productivity.3. Fault diagnosis 故障诊断Fault diagnosis is the process of identifying and troubleshooting problems in an automated system. It involves analyzing data, conducting tests, and using diagnostic tools to pinpoint the cause of a malfunction and propose a solution.4. Safety precautions 安全措施Safety precautions are measures taken to prevent accidents and ensure the well-being of personnel working with automated systems. They include the use of protective equipment, adherence to safety protocols, and regular maintenance of equipment.5. Quality control 质量控制Quality control involves monitoring and inspecting products or processes to ensure they meet specified standards. It includes activities such as testing, sampling, and statistical analysis to identify and correct any deviations from the desired quality.三、相关领域的专业术语1. Industrial automation 工业自动化Industrial automation refers to the use of control systems and software to automate manufacturing processes. It includes the use of robots, PLCs, and other technologies to improve productivity, efficiency, and safety in industrial settings.2. Process control 过程控制Process control involves monitoring and adjusting the parameters of a production process to ensure desired outcomes. It includes the use of feedback control loops, algorithms, and mathematical models to regulate variables such as temperature, pressure, and flow rate.3. Motion control 运动控制Motion control is the process of regulating the movement of machinery and equipment. It involves the use of motors, drives, and feedback systems to control speed, position, and acceleration in applications such as robotics, CNC machines, and conveyor systems.4. Supervisory Control and Data Acquisition (SCADA) 监控与数据采集SCADA is a system used to monitor and control industrial processes and infrastructure. It involves the use of sensors, PLCs, and communication networks to collect data, provide real-time visualization, and enable remote control of operations.5. Programmable Automation Controller (PAC) 可编程自动化控制器A PAC is a type of control system that combines the capabilities of a PLC with those of a PC. It allows for more advanced programming, data processing, and connectivity options, making it suitable for complex automation applications.总结：自动化专业英语是自动化工程领域中不可或者缺的一部份。
Process Control 过程控制
Lesson 4 Process Control1 Process-Control PrinciplesProcess Control is the active changing of the process based on the results of process monitoring. In process control, the basic objective is to regular the value of some quantity. To regulate means to maintain that quantity at some desired value regardless of external influences. The desired value is called the reference value or setpoint.Figure 5.9 shows the process to be used for this discussion. Liquid is flowing into a tank at some rate Qin and out of the tank at some rate Qout. The liquid in the tank has some height or level h. It is known that the flow rate out varies as the square root of the height, so the higher the level the faster the liquid flows out. If the output flow rate is not exactly equal to the input flow rate, the tank will either empty, if Qin > Qout, or overflow, if Qout < Qin.This process has a property called self-regulation. This means that for some input flow rate, the liquid height will rise until it reaches a height for which the output flow rate matches the input flow rate. A self-regulating system does nit provide regulation of a variable to any particular reference value. In this example the liquid level will adopt some value foe which input and output flow rates are the same and there it will stay. If the input flow rate changed, then the level would change also, so it is not regulated to a reference value.Suppose we want to maintain the level at some particular value H in Figure 5.9, regardless of the input flow rate, then something more than self-regulation is needed.Human-Aided ControlHuman-aided control shows a modification of the tank system to allow artificial regulation of the level by a human. To regulate the level so that in maintains the value H it will be necessary to employ a sensor to measure the level. This has been provided via a sight tube. The actual liquid level or height is called the controlled variable. In addition, a value has been added so the output flow rate can be changed by the human. The output flow rate is called the manipulated variable or controlling variable.Now the height can be regulated apart from the input flow rate using the following strategy: The person measures the height in the sight tube and compares the value to the setpoint. If the measured value is larger, the human opens the value a little to let the flow out increase, and thus the level lowers toward the setpoint. If the measured value is smaller than the setpoint, the person closes the value a little to decrease the flow out and allow the level to rise toward the setpoint.By a succession of incremental opening and closing of the value, the human can bring the level to the setpoint value H and maintain it there by continuous monitoring of the sight tube and adjustment of the value.Automatic ControlTo provide automatic control, the system is modified using machines, electronics, or computers to replace the operations of the human. An instrument called a sensor is added that is able to measure the value of the level and convert it into a proportional signal. The signal is provided as input to a machine, an electronic circuit, or a computer, called the controller. This performs the function of the human in evaluating the measurement and providing an output signal to change the value setting via an actuator connected to the valve by a mechanical linkage.2 Identification of ElementsThe elements of a process-control system are defined in terms of separate functional parts of the system.ProcessIn general, a process can consist of a complex assembly of phenomena that relate to some manufacturing sequence. Many variables may be involved in such a process, and it may be desirable to control all these variables at the same time. There are single-variable process, in which only one variable is to be controlled, as well as multivariable processes, in which many variables, perhaps interrelated, may require regulation.MeasurementClearly, to effect control of a variable in a process, we must have information on the variable itself. Such information is found by measuring the variable. In general, a measurement refers to the conversion of the variable into some corresponding analog of the variable, such as a pneumatic pressure, an electrical voltage, or a current. A sensor is a device that performs the initial measurement and energy conversion of a variable into analogous electrical or pneumatic information. Further transformation or signal conditioning may be required to complete the measurement function. The result of the measurement is a representation of the value in some forms required by the other elements in the process-control operation.ControllerThe next step in the process-control sequence is to examine the error and determine what action, if any, should be taken. This part of the control system has many names; however, controller is the most common. The evaluation may be performed by an operator, by electronic signal processing, by pneumatic signal processing, or by a computer. The controller requires an input of both a measured indication of the controlled variable and a representation of the reference value of the variable, expressed in the same terms as the measured value.Control ElementThe final element in the process-control operation is the device that exerts a direct influence on the process; that is, it provides those required changes in the controlled variable to bring it to the setpoint. This element accepts an input from the controller, which is then transformed into some proportional operation performed on the process.3 Process-Control Block DiagramTo provide a practical, working description of process control, it is useful to describe the elements and operations involved in more generic terms. Such a description should be independent of a particular application and thus be applicable to all control situations. A model may be constructed using blocks to represent each distinctive element. The characteristics of control operation then may be developed from a consideration of the properties and interfacing of these elements. Figure 5.10 shows a general block diagram. The controlled variable in the process is denoted by e in this diagram, and the measured representation of the controlled variable is labeled b. The controlled variable setpoint is labeled r, for reference.The error detector is a subtracting-summing point that outputs an error signal e=r-b to the controller for comparison and action.The purpose of a block diagram approach is to allow the process-control system to be analyzed as the interaction of smaller and simpler subsystems. If the characteristics of each element of the system can be determined, then the characteristics of the assembled system can be established by an analytical marriage of these subsystems. The historical development of the system approach in technology is dictated by this practical aspect: first, to specify the characteristics desired of a total system and, then, to delegate the development of subsystems thatprovide the overall criteria..4 Control System EvaluationA process-control systems is used to regulate the value of some process variable. When such a system is in use, it is natural to ask, “How well is it working?” This is not an easy question to answer, because it is possible to adjust a control system to provide different kinds of response to errors. This section discusses some methods for evaluating how well the system is working.The variable used to measure the performance of the control system is the error, which is the difference between the constant setpoint or reference value r and the controlled variable c(t).Since the value of the controlled variable may vary in time, so may the error.In principle, the objective of a control system is to make the error exactly zero, but the control system responds only to errors. Conversely, if the error were zero and stayed zero, the control system would be doing nothing and would not be needed in the first place. Therefore, this objective can never be perfectly achieved, and there will always be some errors. The question of evaluation becomes one of how large the error is and how it varies in time.The purpose of the control system is to regulate the value of some variables. This requires that action be taken on the purpose itself in response to a measurement of the variable. If this is not done correctly, the control system can cause the process to become unstable. In fact, the more tightly we try to control the variable, the greater the possibility of an instability.The first objective, then, simply means that the control system must be designed and adjusted so the system is stable. Typically, as the control system is adjusted to give better control, the likelihood of instability also increases.。
自动化专业常用英语词汇
自动化专业常用英语词汇自动化专业是一门涉及自动控制、机器人技术、工业自动化以及相关领域的学科。
在学习和实践中，掌握一些常用的英语词汇对于自动化专业学生来说非常重要。
以下是一些常见的自动化专业常用英语词汇及其解释。
1. Automation（自动化）Automation refers to the use of technology to control and operate machines or processes without human intervention. It involves the use of various control systems, sensors, and actuators to achieve automatic operation.2. Control system（控制系统）A control system is a set of devices or software that manages and regulates the behavior of other devices or systems. It is used to monitor and control the operation of machines, processes, or equipment.3. Robotics（机器人技术）Robotics is the branch of technology that deals with the design, construction, operation, and application of robots. It involves the study of mechanical engineering, electrical engineering, and computer science to create intelligent machines capable of performing tasks autonomously or with human interaction.4. Industrial automation（工业自动化）Industrial automation refers to the use of various control systems, computer systems, and information technologies to automate industrial processes and manufacturing operations. It aims to increase efficiency, productivity, and safety in industrial settings.5. Programmable logic controller (PLC)（可编程逻辑控制器）A programmable logic controller (PLC) is a digital computer used to control and automate electromechanical processes in industrial settings. It is programmed usingladder logic or other programming languages to monitor and control the operation of machines and processes.6. Human-machine interface (HMI)（人机界面）A human-machine interface (HMI) is a device or software that allows humans to interact with machines or systems. It provides a graphical user interface (GUI) or a touch screen interface for users to monitor and control the operation of machines or processes.7. Sensor（传感器）A sensor is a device that detects and responds to physical or chemical changes in the environment. In automation, sensors are used to measure various parameters such as temperature, pressure, flow, and position, and provide feedback to the control system for decision-making.8. Actuator（执行器）An actuator is a device that converts electrical, hydraulic, or pneumatic energy into mechanical motion. It is used to control and move mechanical components or systems in response to signals from the control system.9. Process control（过程控制）Process control involves monitoring and controlling the variables in a manufacturing or industrial process to ensure optimal performance and product quality. It uses various control strategies and techniques to regulate variables such as temperature, pressure, flow, and level.10. Industrial network（工业网络）An industrial network is a communication system used to connect and exchange data between devices, machines, and systems in an industrial environment. It enables real-time monitoring, control, and coordination of industrial processes and equipment.11. Supervisory control and data acquisition (SCADA)（监控与数据采集）Supervisory control and data acquisition (SCADA) is a system used to monitor and control industrial processes and infrastructure. It collects data from sensors and devices, displays real-time information, and allows operators to control and manage the operation of the system.12. Distributed control system (DCS)（分布式控制系统）A distributed control system (DCS) is a control system that consists of multiple control elements distributed throughout a plant or industrial facility. It allows for decentralized control and coordination of various processes and equipment.以上是一些常见的自动化专业常用英语词汇及其解释。
重庆大学-过程控制-process-control-中文-翻译-第十章(1)
S-loop control solution单环开环控制
1. measure T by TT, 2. compute p by TC,
TT TC
Tsp
3. send the p to the valve
4
Multiloop Systems
Cascade Control
Motivation of动机 Cascade Control
Problem (e): determine Kc of PI controller that guarantees system stable when I=0.5 without cascade
Solution: ➢system is a single-loop system when no cascade ➢characteristic equation of its closed-loop equation is
8
Multiloop Systems
Cascade Control
Cascade Control Solution Reducing the block diagram方块图
Setting Gm1=Gm2=1
where
9
Multiloop Systems
Cascade Control
Reducing the block diagram
FC in slave loop adjusts the regulating valve调节阀
▪ FC compares the desired and measured fuel gas flow rates
▪ responding immediately to fluctuations in the fuel gas flow 立即对波动的燃气速率做出反应
重庆大学-过程控制-process-control-中文-翻译-第一章
What Is Process Control?
A Few Examples
7. Discrete Manufacturing Processes 离散型制造过程
What Is Process Control?
A Few Examples
8. Typical continuous processes典型的连续过程
What Does It Do?
Differences from automatic control theory自动控制理论的差异 What to be controlled?
How Does It Do?如何实现
Formulating the problem制定问题 Control Equipment and Process Equipment控制设备和工艺设备 Modeling the process of the Problem建模过程的问题
4. Watt Centralfugal Speed Governor 瓦特Centralfugal调速器
What Is Process Control?
A Few Examples
5. Level Control液位控制
What Is Process Control?
A Few Examples
Process Control Systems 过程控制系统
College of Automation, Chongqing University
过程控制自动化 重庆大学
Outline of the Introduction
What Is Process Control?
Definition A few examples and forms一些例子和形式
柯美维修模式中英文对照
柯美维修模式中英文对照维修模式中英文对照Service Mode（维修模式）一、 SERVICE'S CHOICE（技术维修选择）1、SHIPMENT DESTINATION （市场地区）2、MAINTENANCE COUNTER （保养计数器）3、IU LIFE STOP MODE （IU 寿命终止模式）4、ID ADJUST （ID 调整）5、VG ADJUST （VG 调整）6、FUSER TEMP. Ad (PLAIN)（定影温度调整（普通纸））7、FUSER TEMP. Ad (THICK)（定影温度调整（厚纸））8、FUSER TEMP. Ad (OHP)（定影温度调整(OHP)）9、LEADING EDGE ERAGE （前边缘消除）10、TRAILING EDGE ERAGE （后边缘消除）11、VERTICAL EDGE ERAGE （上下边缘消除）12、LOOP ADJUST (TRAY1)（波幅调整（第1 纸盒））13、LOOP ADJUST (TRAY2 TO TRAY5)*（波幅调整（第2 纸盒到第5 纸盒）*）14、LOOP ADJUST (DUPLEX)（波幅调整（双面））15、LOOP ADJUST (BYPASS)（波幅调整（手送进纸））16、FLS PAPER SIZE （FLS 纸张尺寸）17、CCD APS SIZE （CCD APS 尺寸）18、GDI TIMEOUT （GDI 超时）二、ADJUST （调整）1、PRN MAIN REGIST （打印主对位）2、PRN SUB REGIST （打印副对位）3、CCD MAIN ZOOM （CCD 主缩放）4、CCD SUB ZOOM （CCD 副缩放）5、CCD MAIN REGIST （CCD 主对位）6、CCD SUB REGIST （CCD 副对位）7、ADF SUB ZOOM （ADF 副缩放）8、ADF MAIN REGIST （ADF 主对位）9、ADF SUB REGIST1 （ADF 副对位1）10、ADF SUB REGIST2 （ADF 副对位2）11、ADF REG. LOOP 1 （ADF 对位波幅1）12、ADF REG. LOOP 2 （ADF 对位波幅2）13、A TDC GAIN （A TDC 增益）14、MODEL SETTING （模式设定）二、ADJUST （调整）1、PRN MAIN REGIST （打印主对位）2、PRN SUB REGIST （打印副对位）3、CCD MAIN ZOOM （CCD 主缩放）4、CCD SUB ZOOM （CCD 副缩放）5、CCD MAIN REGIST （CCD 主对位）6、CCD SUB REGIST （CCD 副对位）7、ADF SUB ZOOM （ADF 副缩放）8、ADF MAIN REGIST （ADF 主对位）9、ADF SUB REGIST1 （ADF 副对位1）10、ADF SUB REGIST2 （ADF 副对位2）11、ADF REG. LOOP 1 （ADF 对位波幅1）12、ADF REG. LOOP 2 （ADF 对位波幅2）13、A TDC GAIN （A TDC 增益）14、MODEL SETTING （模式设定）三、COUNTER （计数器）1、TOTAL COUNTER （总计数器）2、SIZE COUNTER （尺寸计数器）3、PM COUNTER （PM 计数器）4、MAINTENANCE COUNTER （保养计数器）5、SUPPLIES LIFE COUNT. （使用寿命计数）6、APPLICATION COUNTER （应用计数器）7、SCAN COUNTER （扫描计数器）8、PAPER SIZE COUNTER （纸张尺寸计数器）9、MISFEED COUNTER （卡纸计数器）10、TROUBLE COUNTER （故障计数器）四、DISPLAY （显示）1、TONER DENSITY LEVEL （碳粉浓度水平）2、PROCESS CONTROL （过程控制）3、MAIN F/W VER. （主机固件版本）4、ENGINE F/W VER. （引擎固件版本）5、PCL F/W VER.* （PCL 固件版本*）6、NIC F/W VER.* （网卡固件版本*）7、ADF F/W VER.* （ADF 固件版本*）8、MAIN RAM SIZE （主内存大小）9、PCL RAM SIZE* （PCL 内存大小*）10、SERIAL NO. （序列号）11、CUSTOMER ID （用户识别码三、COUNTER （计数器）1、TOTAL COUNTER （总计数器）2、SIZE COUNTER （尺寸计数器）3、PM COUNTER （PM 计数器）4、MAINTENANCE COUNTER （保养计数器）5、SUPPLIES LIFE COUNT. （使用寿命计数）6、APPLICATION COUNTER （应用计数器）7、SCAN COUNTER （扫描计数器）8、PAPER SIZE COUNTER （纸张尺寸计数器）9、MISFEED COUNTER （卡纸计数器）10、TROUBLE COUNTER （故障计数器）四、DISPLAY （显示）1、TONER DENSITY LEVEL （碳粉浓度水平）2、PROCESS CONTROL （过程控制）3、MAIN F/W VER. （主机固件版本）4、ENGINE F/W VER. （引擎固件版本）5、PCL F/W VER.* （PCL 固件版本*）6、NIC F/W VER.* （网卡固件版本*）7、ADF F/W VER.* （ADF 固件版本*）8、MAIN RAM SIZE （主内存大小）9、PCL RAM SIZE* （PCL 内存大小*）10、SERIAL NO. （序列号）11、CUSTOMER ID （用户识别码四、DISPLAY （显示）1、TONER DENSITY LEVEL （碳粉浓度水平）2、PROCESS CONTROL （过程控制）3、MAIN F/W VER. （主机固件版本）4、ENGINE F/W VER. （引擎固件版本）5、PCL F/W VER.* （PCL 固件版本*）6、NIC F/W VER.* （网卡固件版本*）7、ADF F/W VER.* （ADF 固件版本*）8、MAIN RAM SIZE （主内存大小）9、PCL RAM SIZE* （PCL 内存大小*）10、SERIAL NO. （序列号）11、CUSTOMER ID （用户识别码）。
自动化专业英语Unit23-Process_control
Unit23 The Introduction to Process Control①Key Words and Terms1.process n.过程(这里指工业生产过程)2.instrumentation n.仪表装置3.objective n.目标4.block diagram 方框图5.manipulated a.（可）操纵的，manipulated variable 操纵量（指自动控制系统中可以根据需要改变的变量）6.batch a.分批的，间歇（式）的7.actuator n.执行器、执行机构8.tune vt.调节、调整9.pose vt.形成、造成、提出、陈述10.r esidence time 驻留时间11.c atalyst n.催化剂、刺激（促进）因素12.f ail-safe vi. n.失效保护13.v alve stem 阀芯14.f eed forward 前馈15.s et-point 设置点16.a lgorithm n.算法Notations and TranslationThe goal of this chapter is to provide a motivation for, and anintroduction to, process control and instrumentation. After studying this chapter, the reader, given a process, should be able to do the following: •Determine possible control objectives, input variables (manipulated and disturbance) and output variables (measured and unmeasured), and constraints (hard or soft), as well as classify the process as continuous, batch, or semi-continuous•Assess the importance of process control from safety, environmental, and economic points of viewassess v. 估定,评定从安全、环境及经济的角度评估过程控制的重要性。
重庆大学-过程控制-process-control-中文-翻译-第一章
望的最终产品,被称为过程控制
Short examples:
Making of fire for cooking rice (primitive and modern)The fly-ball governor for steam engine control (1774)短的例子:让火煮米饭(原始的和现 代)州长的fly-ball蒸汽发动机控制(1774) Tendency of industrial process control
6. Cross Direction ProceControl十字方向过程控制
•Several hundred sensors and actuators,
•Millisecond operation, •Controlling paper thickness to
within microns!几百传感器和执行器,
16
What Is Process Control?
Summary of the Examples- Forms总结的例子-形式
Discrete Manufacturing, Motion, and Packaging离散型制造、运动、和包装
Robotic Assembly Line in Automotive Production机械的汽车生产流水线 Metal Stamping for the discrete pieces of product 五金冲压为离散件产品
Displays of variables, calculations, commands to valves and
过程控制-专业英语-第一章
1INTRODUCTION TOPROCESS MEASUREMENTAND CONTRLOBJECTIVESWhen you complete this chapter you will be able to:·Define process measurement·Define process control·Calculate simple return on investment from a process control system·Sketch a block diagram of a process control loop·Describe typical industrial processes under process control·Draw simple Process and Instrumentation Diagrams (P&ID) using ISA symbols·Describe the measuring sensor block of a control loop·Describe the controller block of a control loop·Describe the process adjustment block of a control loop·Describe the signals circulating around a control loop1.1 PROCESS MEASUREMENT AND CONTROL DEFINEDProcesses include anything from the heating of your house to the marketing of baby food. For our purposes, however, we will be concerned on1y with industrial processes such as the distillation of crude oil, or the digestion of wood chips to make pulp, or the conversion of pulp to paper, or the fabrication of plastic products such as 1-liter plastic soft drink bottles. These are overall processes and each of them will usually include many subprocesses.Process measurement is defined as the systematic collection of numeric values of the variables that characterize a process to the extent that the process control criteria of the process user are satisfied. As an example, if you require your house temperature to be maintained between l8o C and 24o C with an accuracy of 0.25o C, then your thermostat must measure the temperature and collect its numeric value for your furnace controller so that it will maintain this accuracy As another example, if the owner of a distillation plant making gasoline requires a certain octane range from the plant, then all the measuring and control instruments on the plant must be chosen to work together accurately to ensure that the plant achieves those criteria. As a final example, if the manufacturer of baby food wishes to make mashed carrots for the market, then he will ask a market analyst to acquire data on the potential customers of mashed carrots for babies.The purpose of process measurement is to assist a human or a machine to monitor the status12 of a process as it remains at some steady state or as it changes from one state to another such as heating up crude oil. In most cases the human or machine will guide or force the process to change safely from an initial state to a more desirable state (e.g., forming a plastic bottle). This is process control.1.2 INVESTMENTOf course, the purpose of any process equipment and its measurement and control system is to provide a satisfactory return on its invested capital. The best control system maximizes the return on the whole process plant, not just on the capital invested in the control system. It does this over its lifetime. Therefore, maintenance costs and loss of production costs due to breakdowns should be considered when selecting the measurement and contro1 system. Reliability is a very important aspect in the selection of systems and often worth the added initial costs. Reliability of the system is in itself important. So is the reliability of the system supplier to provide replacement parts and service in the future.An example of justifying the expenditure of $2,353,000 on a rep1acement control system for an existing process, using an old, manual method of control, has the following simple, estimated costs:Annual losses from old control systemOld system losses due to off-spec product $850,000Old system losses due to control system downtime 145,000$995,000Annual savings from new control systemNew system losses due to off-spec product $250,000New system losses due to control system downtime 145,000$395,000Reduction of losses due to new system $600,000Extra annual operating and maintenance cost of new system 115,000Annual savings from new system $485,000One-time costs of new systemLowest price vendor's price $1,875,000Spare parts costs 125,000Installation costs 265,000Training costs for p1ant personnel 88,000$2,353,000 Expected return on investment = 000,2353$%100yr /000,485$ =20.6%/yr Payback period = yr/000,485$000,2353$ = 4.85 yearsThis example shows in a simple way the method of comparing engineering projects in order to select the ones that will make the most profit for the company planning to make improvements to its plant. For example, if the company has many possible projects to invest its money in, it will choose to rank them according to their return on investment. The ones with a high return on investment will usually be chosen over the ones with low return on investment.1.3 CONTINUOUS AND DISCRETEPROCESS CONTROL LOOPSThere are two main forms of process contro1: continuous and discrete (or on/off). The continuous form of process control implies smooth even measurement of the process variable over a fairly wide range that is finely resolved into many hundreds or thousands of values. For examp1e, the temperature in your home may cover a continuous range of 0o C to 40o C resolved into at least 256 values, or spacings of 0.156o C. The discrete form of process control implies a discrete variable with only a few (at least two, such as on and off) status points covering its range. For example, an electric motor may be stopped (off) or running (on). This book concentrates on continuous control.Continuous process control emphasizes feedback using a closed loop. Figure 1.l shows a typical closed loop. An example of a closed loop is cruise control on an automobile. The driver sets a certain desired speed as the set-point signal and places the car on cruise control. If the feedback signal (speed of the car) is less than the set-point signal, and a positive error (difference between set-point speed and feedback speed) exists, then the contro1ler increases its output signal. The output signal opens the throttle (the process adjusting device) of the engine (the process), causing the car to speed up. The speed sensor detects this increase in speed (the measured process variab1e) and sends a stronger feedback signal to the controller. This action continues until the feedback signal equa1s the set-point signal, and then the contro1ler output signal maintains its value, keeping the car at the desired speed.Discrete process control emphasizes Boolean logic using gates and timers. Figure 1.2 shows a generalized logic diagram. An example of discrete process control is the control of a crossing gate at a railroad crossing. Two train sensors are used on the railway tracks. One is placed on the tracks at one side of the crossing and the other on the tracks on the other side of the crossing. If either sensor detects a train, the crossing gate on the highway should close. However, if a short train appears it may be between the sensors and the crossing gate may open at an incorrect time. The control logic should not let this happen; it should only allow the gate to open after the train passes over the second sensor. In this case the process is the flow of traffic over the highway and over the railway. The railway train sensors are the process status sensors, and they produce the discrete input status signals for the programmable logic controller. Based on these signals, the programmable logic controller decides when to change the discrete output status signal. This signal operates the motor (process adjusting device) driving the gate open or closed.1.4 THE PROCESS BLOCK OF A CONTROL LOOPFigure 1.1 is a most important figure. The four blocks and the signals that connect them34 together will be referred to frequently The most important block is the process block because itdictates how the other blocks are expected to perform. The measuring sensor must be selected to measure the process variable that is associated with the process. The process adjusting device must be selected to adjust the adjusted —or manipulated —process variable that is associated with the process.5 The adjusted or manipulated variable adjusts the process so that the measured process variable approaches more closely to the set-point value. For example, in an automobile on cruise control, the throttle position is the adjusted process variable, and it adjusts the fuel flowing to the engine. As the fuel flow is increased, the speed of the auto increases. The speed of the auto is the measured process variable, and if the control system is functioning correctly the speed should be approaching more closely to the set-point value.In order to describe control loops, ISA symbols (described in Appendix A) have been used by many large industrial companies for more than 50 years. Each instrument or instrument function is identified with a circle (or “balloon ”), some letters, and a number as its symbol. Most of the letters are defined by ISA, but some may be defined by the user. The process symbol is not usually defined by ISA and here the user may be creative. Every control loop has hardware or software that is represented by the four blocks shown in Figure 1.l. For each loop a process and instrumentation diagram (P&ID) is prepared. For example, as shown in Figure 1.3,there are usually many loops shown on one large diagram for a major process. Each loop on the P&ID uses ISA symbols to show the particular devices that perform the functions shown in Figure 1.1. Figure 1.3 shows a typical liquid flow control loop (F-212) supplying liquid from a pipe to a tank. Figure l.3 also shows a typical liquid level control loop (L-141) adjusting the flow out of the tank to maintain the tank level at the set point of the level controller (LlC-141). By studying AppendixA you should be able to conclude that the letters and numbers associated with each ISA symbol represent the following:Flow Loop F-212FE-212FT-212FIC-212FY-212FV-212Level Loop L-141 LT-141LIC-141L Y-141LV-141 Flow primary element (e.g., orifice plate or venture)Flow transmitterFlow indicating controllerFlow relay to compute function (computes pneumatic signal to correspond to electric signal value)Flow valve (adjusts flow to correspond to pneumatic signal value)Level transmitterLevel indicating controllerLevel relay or compute function (computes pneumatic signal to correspond to electric signal value)Level valve (adjusts flow to correspond to pneumatic signal value)1.5 THE MEASURING SENSOR BLOCK OF A CONTROL LOOPThe measuring sensor block of flow loop F-212 in Figure 1.3 includes both the flow element and the flow transmitter, whereas the measuring sensor block for level loop L-141 needs only the level transmitter. Depending on the process, the block may include several instrument functions. The P&ID shows all the instrument functions so that the detailed design drawings wil1 reflect the complete loop and so that any engineering cost estimates will be complete.Measuring sensors are described for many of the common process variables in Chapter 2. However, there is an enormous number of sensors for the less common type of process variables that are not described. If you become deeply involved with specifying measuring sensors, then you will want to obtain some of the reference texts listed at the end of Chapter 2.Notice the dotted line coming from the flow and level measuring sensors in Figure l.3 to their controllers. This represents the electrical feedback signal (corresponding to the measured process variable) that is transmitted from the measuring sensor to the controller. The most important feature of a measuring sensor is the relationship of the feedback signal to the measured variable. Measuring sensors must maintain this relationship in order to achieve an accurate calibration.1.6 THE CONTROLLER BLOCK OF A CONTROL LOOPThe controller block of the control loop may be hardware or software. Hardware type electronic controllers receive a feedback signal value from the measuring sensor and compare it with the set-point value (usually dialed in to the hardware by the process operator) to obtain an error value. If the feedback signal has the same value as the set point, the error is zero, and this means that the measured variable equals the set point. The error signal generates an output signal from the controller that is the signal sent to the process adjusting block. Generally there may be three functions with gain settings that make up the controller output signal. These functions are the error itself, its derivative, and its integral. Whether the controller block is hardware or software, it calculates its output signal in the same way Be careful not to assume that the controller output signal is proportional to the feedback signal. Even though they may have the same range (4-20 ma6DC) they are related in a fairly complicated mathematical way1.7 THE PROCESS ADJUSTMENT BLOCKOF A CONTROL LOOPThe process adjustment block manipulates or adjusts a process variable in order to change the measured process variable to bring it closer to the set point. For example, in flow loop F-2l2 of Figure 1.3, the adjusted process variable is the measured process variable, flow In level loop L-14l, however, the adjusted process variable is the flow out of the tank, which is quite different from the measured process variable, the tank liquid level.Chemical-type process control loops usually adjust fluid flow with control valves. These are commonly the process adjusting device. However, there are many other types of process adjusting devices, including electric motors, electric heaters, pneumatic pistons, pumps, fans, and so on.1.8 THE SIGNALS CIRCULATING AROUND A CONTROL LOOPEach block of a control loop has an input signal and an output signal. The input signal of one block is the output signal of another block. The units of a signal may be degrees Celsius or milliamperes or some other physical units. If a range for the feedback signal to the controller block, such as 4-20 ma DC, is settled upon, however, then this may also be considered as 0－100%.If we look at the flow loop F-212 in Figure 1.3, then we can imagine a typical steady-state gain (an output signal corresponding to an input signal) of each block around the loop. For example:Instrument Input Signal Range Output Signal RangeFE-212 0-100 GPM 0-100 in. of waterFT-212 0－100 in. of water 4-20 ma DCFIC-212 4-20 ma DC 4-20 ma DCFY-212 4-20 ma DC 3-15 psigFV-212 3-15 psig 0-85 GPMIf we were to open the loop at the feedback signal and insert a sine wave signal to the controller for the feedback signal, then we will see a corresponding sine wave signal appear at the feedback signal from the measuring sensor. If this sine wave has an amplitude in phase with, and greater in value than, the signal injected into the controller, then we obviously have an unstable loop. The way these signals interact with one another establishes the way our closed control loop will perform. Any oscillation should dampen down quickly to a steady state value. For each loop, the possibility of unstable operation must be considered, and the loop must be tuned to ensure stable operation.PROBLEMS AND LAB ASSIGNMENTS1.1 A company’s process makes a product that is completely sold out each year no matter howmuch it produces. With the simplest manual control, there are average annual lossestotaling $1,260,000 due to off-spec product or downtime due to control system faults.7With a sophisticated distributed control system, these losses could be reduced to $225,000.This new control system is quoted by the lowest cost vendor as $2,875,000 plus $260,000for recommended spare parts. The consultant estimates installation costs to be anadditional $470,000. Training of the operator crews and maintenance crews is estimated tobe $185,000.The extra annual maintenance costs are quoted as $220,000. What is theannual percent of return on the invested capital for the control system, and what is thepayback period?1.2 Describe the logic that you would use to keep the railroad crossing gate closed in thediscrete process control example associated with Figure 1.2 when a short train is betweenthe two train sensors.1.3 Identify the control loop block associated with each ISA symbol shown in Figure l.3.1.4 Draw a P&ID diagram using ISA symbols for a temperature control loop that controls thetemperature of the liquid in the tank of Figure 1.3 using a steam heating coil located in thetank liquid.1.5 Continuous (or Analog) Control Loop 1dentification and OperationObjective. To be introduced to ISA symbols, to identify the features of a continuous process control loop, and to operate the loop in the automatic (closed loop) mode andmanual (open loop) mode.Equipment: A demonstration process control loop using a commercial analog controller. The preferred system is a liquid level loop with a plexiglass tank tower about 6or 8 inches in diameter and 50 inches high.Alternatively a computer simulation of a tank under automatic level control, such as TANKSIM, may be used.*Identification Procedure: Use an e1ectronic or pneumatic liquid level control loop and identify all the features shown in Figure 1.1. This loop should have its control valveon the inlet to the tank and a manual valve adjusting the flow of liquid (water) out of thetank to a drain. Alternatively the manual and automatic control valves may replace oneanother. Draw the loop using ISA instrumentation symbols (see Appendix A). Prepare alist including each device with the ISA tag that you have assigned it. In the list include themanufacturer's name and model number and the important characteristics that describeeach device.Operation Procedure:Have your instructor ensure that the controller is correctly tuned. Mark in pen on the chart all your changes to the control loop as you make them.Set the loop in automatic (closed loop) operation at 50% of full tank level with a moderateamount of liquid flowing out of the tank (the manual valve position at 50% open). If, atany time, it looks as if the tank might overflow quick1y close the valve on the inlet line tothe tank. Obtain a record of the variation in the level and valve position as the level settlesat or near 50%. Change the level set point to 75% and obtain another record of the leveland valve stem changes until they have settled at or near 75%.Switch the controller to manual (open loop) operation and adjust the inlet valve *See Woodford, A. T 1987. TANKSIM A TW Software.8manually to 5% open. Open the outlet valve to 50% open. Record the value of the level and valve position as they change and the level settles out at 0%. Retain the controller in manual (open loop) with the inlet valve at 5% open and close the flow of liquid to the outlet. Record the value of the level as it rises and, at 25% of full tank level, reopen the outlet valve to the previous 50% position. Manually adjust the inlet valve opening to 80% and record the time it takes to fill the tank to 65% full, and then switch the contro1ler back to automatic (closed loop) mode at a level set point of 35%. Let it settle and then close the tank outlet valve and record the value of level and valve position as they settle.Shut down this control system by shutting off the water, air, and electricityConclusions: What do you do to the control loop when you switch from automatic to manual mode? Where does the change occur in the loop? What signal in Figure l.1 do you adjust when the loop is in manual mode? When the loop is in automatic (closed loop) control, how do you disturb or upset the loop? How does the controller affect the loop in manual and in auto modes?REFERENCES1. Webb, John W and Reis, Ronald A. 1995. Programmable Logic Controllers Principles andApplications 3rd ed. Upper Saddle River, NJ: Prentice Hall.9。
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2. pH Control Manual手册 Automated
pH control
6
What Is Process Control?
A Few Examples:
3. Room temperature control
7
What Is Process Control?
A Few Example
4. Watt Centralfugal Speed Governor 瓦特Centralfugal调速器
8
What Is Process Control?
A Few Examples
5. Level Control液位控制
9
What Is Process Control?
……
20
How Does It Do?
Formulating the Problem Statement制订问题的声明
Problem Statement:
having
Heating up the temperature in a room is a process:
the specific, desired outcome to reach,为了达到具体的，理想的结果
A Few Examples
6. Cross Direction ProceControl十字方向过程控制
•Several hundred sensors and actuators, •Millisecond operation, •Controlling paper thickness to within microns!几百传感器和执行器,
maintaining keeping
a defined temperature (setpoint),
temperature constant over time. 一直保持温度恒定
21
How Does It Do?
Formulating the Problem Terminology in the process制定问 题术语过程中
控制
A Day in a Life of a Plant Operator
3
What Is Process Control?
Definition
The
technology of
a series of events to transform a material into a desired end
Disturbance or “Load" Variables造成控制变量偏离设定值被称为“负载“变量 或干扰
22
How Does It Do?
Formulating the Problem
Controlling
the temperature
The Temperature Cycles Periodically温度 周期定期 23
The
The
temperature is the Controlled Variable (CV)
heater state is called the Manipulated Variable加热状态被称为操纵变
量
Factors
causing CV to deviate from their set points is called the
Robotic
Metal Stamping for the discrete pieces of product 五金冲压为离散件产品
Continuous
Production of Fuels, Chemicals连续生产的燃料、化学品
Room Temperature Nucleus
Batch
Valve opening determined by the signal from computer
Displays of variables, calculations, commands to valves and historical data are in the centralized control center.显示变量的
微操作,控制纸张厚度和在微米!
10
What Is Process Control?
A Few Examples
7. Discrete Manufacturing Processes 离散型制造过程
11
What Is Process Control?
A Few Examples
8. Typical continuous processes典型的连续过程
16
What Is Process Control?
Summary of the Examples- Forms总结的例子-形式
Discrete
Manufacturing, Motion, and Packaging离散型制造、运动、和包装
Assembly Line in Automotive Production机械的汽车生产流水线
Formulating Control
Equipment and Process Equipment控制设备和工艺设备 the process of the Problem建模过程的问题
2
Modeling
Introduction to Process Control
Operator’s View of Process Control操作员的观点的过程
12
What Is Process Control?
A Few Examples
9. Typical non-continuous processes
13
What Is Process Control?
A Few Examples
10. A Semi-Continuous Process半连续过程
25
How Does It Do?
Two Classes of Process Control两级过程控制
Regulatory
control- disturbance change 常规控制
The transient behavior when a disturbance enters A control system should be able to return each controlled variable back to its setpoint 当一个扰动暂态行为进入一个控制系统应
controlled variables at the desired values products with consistent quality when raw material
Maintaining
保持控制变量在期望值 Manufacturing
properties change?生产质量稳定的产品，原料性质改变时？
Tedency:
Being Compueterized, Automatized, and Instrumented by smart sensors and MEMS计算机化，自动化，和动态化由智能传感器和微机电系统
Sensors, local indicators, and valves in the process传 感器、当地的指标,和阀门 在这个过程中
Responding
dangerous situations with given time
危险的情况下和给定的时间响应
Being
Specialized by transducer作为专业的传感器
Smart MEMS
sensors 微机电系统
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What Does It Do?
What To Be Controlled?
Typical
Controlled Variables
Temperature, Pressure, Flow, Level, Concentration浓度 Physical
property物理性质
Beyond
Position,
the Typical
Velocity, and Acceleration in Motion位置、速度和加速度运动
controlling
product is called process control.控制技术的一系列事件把资料达到所希望的
最终产品,被称为过程控制
Short
examples:
of fire for cooking rice (primitive and modern)The fly-ball governor for steam engine control (1774)短的例子:让火煮米饭(原始的和现代)州长的 fly-ball蒸汽发动机控制(1774) Tendency of industrial process control
How Does It Do?
Control (verb)
to maintain desired conditions in a physical system by adjusting the selected varialbles in the system 保持理想条件在一个物理系统通过调节系统中变量
Control室温控制
Chemical Reactor核化学反应器
Production of intermediate/end products批量生产中间/ቤተ መጻሕፍቲ ባይዱ端产品
Adhesives
and glues Food, Beverages, and Medicine
17
What Is Process Control?