第十二次课：PART 5 Proce Control
UNIT 3A: P Controllers and PI Controllers
背景知识：PID控制（比例、积分、微分控制）是在工业控制中使用得很广泛的一种方法。具有简单、直观和容易调试的优点。所谓比例控制，是指控制器的输出信号与误差信号成比例，而积分控制则是指控制器的输出信号与误差信号的积分成比例。
New Words: reverse-acting controller 反作用控制器direct-acting controller 正作用控制器 ultimate gain 临界增益surge tank平衡箱 解释：
The proportional controller is the simplest type of controller, with the exception of the on-off controller, which we shall not discu here.除了关断控制器（我们在此不讨论）之外，比例控制器是最简单的控制器。
Since the input and output ranges are the same(3~15psig or 4~20mA), the input and output signals as well as the set point, are sometimes also expreed in either fraction or percent of range.因为输入和输出信号的范围是相同的，输入、输出信号以及设置点有时用分数或者百分比来表示。
In cases in which the proce can be controlled within a band from the set point, proportional only controller are sufficient.在一些场合，过程变量仅仅要求控制在设定值的周围，纯比例控制器就足够了。
The smaller the value of τ1, the steeper the response curve, which means the faster the controller response become.τ1的值越小，响应曲线就越陡，即意味着控制器响应越快。
UNIT 4
A: Indicating Instruments
背景知识：显示仪表是过程控制中使用广泛的一种仪表。主要分为模拟（指针）仪表和数字式（数码管）仪表两种。最近使用计算机屏幕显示变得越来越多。
阅读至第225页第一行
New Words:
aembly n.部件producev.显示、展现alphanumerica.字母数字组成的dialn.刻度盘gage=gaugen.测量仪表whereinadv.在哪个地方、在哪点上speak against 作不利于„„的陈述swingv.摇摆 annunciatorn.信号指示器pseudoa.假的、伪的ingenuityn.灵巧 pyrometrica.高温测量的pyro （前缀） 火、高温、热conen.圆锥体pyrometric cone测温锥crayonn.粉笔、蜡笔kilnn.窑
解释：
For convenience, indicators also may be claified as (1) analog indicators in which all or portion of a calibrated scale is in evidence so that the observer sees the indication in continuum so to speak against all or part of the total range within which the indicator may swing， and (2) digital indicators in which information is indicated a piece at a time.方便起见，指示仪表可以分为 （1）模拟显示仪表，其校准的刻度的部分或者全部都是可见的，观察者可以连续地读数，但是其不利的一面是指针在显示仪表的部分或者全部范围内会摇摆；（2）数字仪表，其每次显示一个值。
There are several forms of indication, reasonably uncommon except for very specific purposes, which illustrate the ingenuity that instrument engineers have applied to data display problems.The pyrometric cone and colored crayons and paints which indicate(historically) whether or not a certain temperature range has been exceeded serve a real need in certain high-temperature measurement situations, particularly where motion, as in tunnels and kilns, is involved.
有几种显示形式，用于非常特殊的目的，展示了仪表工程师在解决数据显示问题时的灵巧。测温锥、彩色粉笔、蜡笔可以表明温度在过去是否超过了某个范围，这在某些高温测量是非常需要的，特别是在移动过程中，例如隧道窑。
B: Control Panel
背景知识：控制盘是控制系统（过程）与操作员之间的界面。常规的控制盘是一个钢的框架，上面装有各种显示仪表、控制仪表、报警装置和控制按钮。现在越来越多的控制系统的人机界面已经由计算机界面（屏幕、键盘、鼠标）等取代。
New Words:
literally adv.照字义、确实地accommodate v.为„提供空间、为„提供方便subjecta.主观的 anthropomorphica.人类形态学的anthropo (前缀) 人类的、人的–morph- （词根） 形态、结构withoutprep.在„范围以外
human engineering 人机工程
解释：
The control panel should be designed to effectively sort out and separate information elements so that the operator’s attention during any time of emergencyor special situations will not be diverted to the information of leer importance, or worse, of complete irrelevance.控制盘应该这样设计，对信息进
行分类和隔离，使得操作员在紧急情况或特殊情况时为一些完全不相干的次要或者错误信息而分神。
All the foregoing objectives and more are subject, of course, to trade-offs wherein cost must be weighed against projected gains.所有前述的目标以及其他一些目标都是主观的，当然，投资与预期收益之间必须进行权衡。
Earlier instruments eentially were not designed with their mounting on a panel as a factor of ultimate importance.The situation had reversed in the late 1970’s, but not without having had to go through several steps in a panel design revolution, including full-graphic and semigraphic panel design.
早期的仪表设计并没有将其要安装的面板作为一个非常重要的因素来考虑。这些情形在20世纪70年代后期有了根本改变（包括全图和半图解面板设计），由于必须要经过面板设计革命的几个步骤，也没有超出范围。 练习十二
1、翻译224页最后一段。
2、文稿阅读：
New Zealand'sand Trade (MFAT) has confirmed that a man from New Plymouth is being detained in Pre Aociation reported Tuesday.
Andreas Schafer's family first feared he was being held in Iraq about a month ago after receiving an email suggesting he had been detained by the American-led Coalition Provisional Authority which administers the country.
However fears were held for his safety after the MFAT checked through diplomatic channels and found he was not being detained by American authorities.
MFAT spokesman Jonathan Schwa said Tuesday that the MFAT this week received information confirming Schafer had been detained in Iraq.
He refused to comment on who was holding Schafer, other than to say it was not an insurgent group.
Schafer was alive and well, but the MFAT was seeking more information on where he was being held and why, Schwa said.
The spokesman would not comment on what Schafer was doing in Iraq.上次作业参考答案“
“和原来的系统相比，温度控制精度提高到±0.5℃，能量消耗下降4%” Comparing with the original system, the temperature control accuracy of system is up to±0.5℃ while the energy consuming is decreased by 4%.
谚语：
A littlepot soon hot.量小易怒/狗肚子盛不了四两油。
Still waters run deep.流静水深，人静心深。
