Process control systems serve two different purposes. Generally the first of these purposes is to effect a change in a certain output variable, commonly encountered in the startup of a process. The second of these is to regulate or hold an output variable constant despite any changes in an input variable, which usually cannot be easily managed [1]. In order to discuss process control, in detail it is necessary to define several terms. A control loop …showed first 75 words of 1924 total…

…showed last 75 words of 1924 total…