How to Design a PID Controller

A proportional-integral-derivative (PID) controller is a type of control loop feedback mechanism that finds wide usage in industrial control systems. In fact, PID is the most commonly used of all feedback controllers. The basic job of a PID controller is to minimize the error value between a measured process and the desired set-point by adjusting the control inputs of the process. A PID controller can be of immense use as it proves to be the best controller in a system in the absence of any knowledge about the underlying process. Designing a PID controller is technical, but nevertheless a simple process.

Things You'll Need

• PID controller algorithm
• Dynamic process data
• First order plus dead time (FOPDT) model, appropriate for process data

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Instructions

1. • 1

     Specify the design level of operation. Collect all the dynamic process data that is practical to the design level.

   • 2

     Fit an existing first order plus dead time (FOPDT) model to the process data. Obtain the initial controller tuning values by using the resulting model parameters.

   • 3

     Improve the rise time of the process by adding a proportional control. Improve the overshoot by adding a derivative control. For eliminating any steady-state error, add an integral control.

   • 4

     Keep adjusting each control until you achieve the desired overall response from the controller.