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1、Lesson 15 Sensor Technology,Section I Words and PhrasesSection II Text and TranslationSection III Exercises and Answers,词,英,汉,练,答,Next,End,Section I Words and Phrases,susceptible sE5septEbladj.易受影响的，尤其敏感的 deterioration di7tiEriE5reiFEnn. 变坏, 退化, 堕落inferential 7infE5renFEladj.推论性的valve vAlvn.阀damper
2、5dAmpEn. 阻尼器，抑制因素synonymous si5nCnimEsadj.同义的implementation 7implimen5teiFEnn.执行,Above,Next,End,Topic,Section I Words and Phrases,monitor 5mCnitEn.班长, 监视器, 监控器v.监控virtually 5v:tjJElI adv.事实上, 实质上analog 5AnElC n.类似物, 模拟物bus bQs n.公共汽车，数据传送总线，总线，母线laptop n.便携式电脑diagnose 5daiEnEuzv.诊断optimize 5Cptimaiz
3、vt.使最优化simulation 7simju5leiFEnn.仿真, 假装，模拟wear wiEvt. 磨损,Topic,Above,Next,End,Section II Text,Technological advancements in process monitoring, control and automation over the past decades have contributed greatly to improve the productivity of virtually all manufacturing industries throughout the w
4、orld.While 90% of global production is still controlled by analog instrum-entation, almost all the controls installed as a part of a new plant or plant expansion are Digital Control Systems1 DCS connected by digital networks. Nowadays, in this era of digital buses, one can plug in a laptop or use a
5、wireless hand tool to instantly establish access to all the data, displays and intelligence that resides anywhere on the DCS network. This capability, in combination with the self-turning, self-diagnosing and optimizing features of modern process control, makes both startup acti-vity and operational
6、 routines much easier and more efficient. Similarly, Distributed Control Systems2 DCS offer process modeling and simulation, something that can improve operator training a great deal. An accurate simulation model allows operators to train under live conditions without exposing the plant to the conse
7、quences of their mistakes.,Topic,Above,Next,End,汉,Section II Text,The following paragraphs will provide information to engineers, pro-fessionals and everybody who is interested in process automation and control. Controller System for Industrial Automation The element linking the measurement and the
8、final control element is the controller. Before the advent of computers, the controllers are usually single-loop3 PID4 controllers. These are manufactured to execute PID control functions. These days, the controllers can do a lot more. However, easily 80 to 90% of the controllers are still PID contr
9、ollers. Analogue vs Digital Controllers It is indeed difficult to say that analogue controllers are definitely better than digital controllers. The point is, they both work. Analogue controllers are based on mechanical parts that cause changes to the process via the final control element. Again like
10、 final control elements, these moving parts are subjected to wear and tear over time and that causes the response of the process to be somewhat different with time. Analogue controllers control continuously.,Topic,Above,Next,End,汉,Section II Text,Digital controllers do not have mechanical moving par
11、ts. Instead, they use processors to calculate the output based on the measured values. Since they do not have moving parts, they are not susceptible to deterioration with time. Digital controllers are not continuous. They execute at very high frequencies, usually 2-3 times a second. Process Control
12、Elements in the Loop A simple process control5loop consists of three elements： the measurement, the controller and the final control element. Measuremen- ts have got to be one of the most important equipment in any processi-ng plant. Any decision made on what the plant should do is based on what the
13、 measurements tell us. With the advent of computers, it is now possible to do inferential measurements, meaning telling the val-ue of a parameter without actually measuring it physically. Final control elements can refer to three things, control valves, var-iable speed drives and dampers. In any che
14、mical process plant, more than 90% of the time, a final control element is a control valve. The is-sues relating to final control elements will be most relevant to control valves although they are applicable to a large extend to dampers and in some cases variable speed drives.,Topic,Above,Next,End,汉
15、,Section II Text,What is Advanced Process Control Nowadays, advanced control is synonymous with the implementat-ion of computer based technologies. It has been reported thatadvan-ced process control can improve product yield; reduce energycons-umption; increase capacity; improve product quality and
16、consisten-cy; reduce product giveaway; increase responsiveness; improved process safety and reduce environmental emissions6. Depending on an individuals background, advanced process con-trol may mean different things. It could be the implementation of feed forward or cascade control schemes, of time
17、-delay compensators, of self-tuning or adapti-ve algorithms or of optimization strategies. Here, the views of academics and practicing engineers can differ significant- ly. We prefer to regard advanced control as more than just the use of multi-processor computers or state-of-the-art7 software envir
18、onments. Neither does it refer to the singular use of sophisticated control algorit-hms. It describes a practice, which draws upon elements from many disciplines ranging from Control Engineering, Signal Processing, Stati-stics, Decision Theory, Artificial Intelligence8 to hardware and software engineering.,
