[Instrumentation interview question ]What is a ‘controller’? Area of application?

Standalone controller (PID)

A controller is an instrument used for controlling a process variable (measurement). Its continuously monitors the error signal and gives a corrective output to the final control element.

a    measurement variable
      desired variable
   deviation
      output

Measurement variable: It is the demand variable measured and controlled.

Desired Variable: it is the demand signal (set point) to which the process variable is controlled.

Deviation: it is the error signal caused by the difference between the measurement and the demand signal.

Output: It is the corrective signal from the controller to the final control element.
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6 comments:

  1. What are the different types of controllers? and List of them?

    ReplyDelete
  2. Hi there, can u describe what is "Z" mean exmple : 61-ZIT-8001
    What exactly is mean

    ReplyDelete
  3. please give correct answer about PID controller and where it is used and Its working principle.

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  4. PID controller means Proportional Integral and Derivative controller. The difference between a measured value and set point value can be calculated by a PID controller and it will minimize the error by its manipulated variables.

    There are mainly three types of PID Controllers
    1.P-controller
    2.I-controller
    3.D-Controller
    and they can also be used by combinations like PI-controller and PD-controller

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