PID Controller optimal tuning

A controller is the most important part of an automatic control system. Its main purpose is to receive the signals from a transmitter and to compare it with a reference value. Depending on the error the controller sends a control signal to an actuator, so that the controlled variable to be equal with the reference value. The most used algorithm by a controller is the PID algorithm. In this paper, two methods of determining the optimum values of the tuning parameters for the PID controller will be presented, using case studies. The optimization criteria are the integral criteria, the square of the error between reference and controlled value being taken into consideration. The results consisted in the optimal values of the PID tuning parameters (gain and reset) for the analyzed cases associated to a temperature control system.