Lesson 15 Sensor TechnologyvSection I Words and PhrasesvSection II Text and TranslationvSection III Exercises and Answers词英汉练答Next End Section I Words and Phrasesvsusceptible sE5septEbladj.易受影响的， 尤其敏感的 vdeterioration di7tiEriE5reiFEnn. 变坏, 退化, 堕落vinferential 7infE5renFEladj.推论性的vvalve vAlvn.阀vdamper 5dAmpEn. 阻尼器，抑制因素vsynonymous si5nCnimEsadj.同义的vimplementation 7implimen5teiFEnn.执行Above Next End Topic Section I Words and Phrasesvmonitor 5mCnitEn.班长, 监视器, 监控器v.监 控vvirtually 5v:tjJElI adv.事实上, 实质上vanalog 5AnElC n.类似物, 模拟物vbus bQs n.公共汽车，数据传送总线，总线， 母线vlaptop n.便携式电脑vdiagnose 5daiEnEuzv.诊断voptimize 5Cptimaizvt.使最优化vsimulation 7simju5leiFEnn.仿真, 假装 ，模拟vwear wiEvt. 磨损Topic Above Next End Section II TextTechnological 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 world.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 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 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 consequences of their mistakes.Topic Above Next End 汉 Section II TextThe following paragraphs will provide information to engineers, pro-fessionals and everybody who is interested in process automation and control.Controller System for Industrial AutomationThe element linking the measurement and the 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 controllers.Analogue vs Digital ControllersIt 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 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 TextDigital controllers do not have mechanical moving parts. 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 Elements in the LoopA simple process control5 loop 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 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 chemical 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 Section II TextWhat is Advanced Process ControlNowadays, advanced control is synonymous with the implementat-ion of computer based technologies. It has been reported that advan-ced process control can improve product yield; reduce energy cons-umption; increase capacity; improve product quality and 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