外文资料翻译---系统设计和补偿技术(编辑修改稿)

外文资料翻译---系统设计和补偿技术(编辑修改稿)内容摘要：

agnitudes of the analog input ,if x si the analog input,the digital output is given by y=Q(x ) Where Q is the quantizing function. The function x(t) is a discretetime operation of digital control systems involves quantization both in amplitude and in s hall next present the definitions of several terms. transducer is a device which converts an input signal into an output signal of another form.(The output general,depends on the past history of the input). Analog analog transducer is a device which converts an input signal into an ouput signals occur only at discrete instants of time (usually periodic),but the magnitudes of these signals may be any value within the physical limitations of the system. Sampleddata is a transducer in which the input and output signals occur only at discrete instants of time(usually periodic),but the magnitudes of the signal,as in the case of the analog transducer,are unquantized. 无锡职业技术学院 外文翻译 5 Digital digital transducer is one in which the input signal is a continuous function of time and the output signal is a quantized signal which can assume only certain discrete levels. Analogtodigital digitaltoanalog transducer is one in which the input signal is a quantized signal and the output signal is a smoothed continuous function of time. Analog controllers and digital considering the types of controllers which are used in industrial control system,we may divide them into the following three categories: Analog controllers or puters:Analog controllers or puter represent the variables in the equations by continuous physical controllers can be designed which will satisfactorily serve as nondecision making controllers. Digital controllers or puters:These operate only on is an important function in digital controllers,and they are currently being used for the solution of problems Involving the optimal overall operation of industrial plants. Analogdigital controllers or puters:These are often called hybrid are binations of amalog controllers and digital of high performance controllers are of this type. Advantages of digital controllers over analog of the advantages of digital controllers over amalog controllers may be summarized as follows: (1)Digital controllers are capable of performing plex putations with constant accuracy at high puters can have almost any desired accuracy in putations at relatively little increase in the other hand,the cost of analog puters increases rapidly as the plexity of the putations increase if constant accuracy is to be maintained. (2)Digital controllers are extremely versatile. By merely issuing a new program,one can pletely change the operations being feature is particularly important if the control system is to receive operating information or instructions from some puting center,where economic analysis and optimization studies are being made. Because of the inability of conventional techniques to adequately handle plex control problems,it has been customary to subdivide a process into smaller units and handle each of these as a separate control problem. Human operators are normally used to coordinate the operation of advances in puter control systems have caused changes in this use of industrial process developments in largescale puters and mathematical methods provide a basis for use of all available information in the control conventional control,this part of the control loop is being done directly by humans. Computer control of plex trends in the control of largescale systems are to consolidate the multiplicity of independently controlled units into single optimally controlled industrial process control system,it is,in general,not practical to operate for a very long time at steady state because certain changes in production requirements,raw materials,economic factors,and processing equipment and techniques,may ,the transient behavior of industrial processes must be taken into there are interactions among process variable,using only one process variable for each control agent is not suitable for really plete use of puter control,it is possible to take into account all process variables together with economic factors,production requirements,equipment performance,etc..,and to thereby acplish optimal control of industrial processes. Note that a system capable of controlling a process as pletely as possible will have to solve plex more plete the control of industrial processes. Note that a system capable capable of controlling a process as pletely as possible will have to solve plex more plete the control,the more important it is that 无锡职业技术学院 外文翻译 6 the correct relations between operating variables be known and be system must be capable of accepting instructions from such varied sources as puter and human operators and must also be capable of changing its control subsystem pletely in a short time. Introductions to PID controllers PID controllers can be standalone controllers (also called songle loop controllers), controllers in PLCs, embedded controllers, or software in Visual Basic or C puter programs. PID controllers are process controllers with the following characteristics: Continuous process control Analog output(also k。