Glossary
Simplified models of aperiodic systems FOR their PID control. Tuning from the step response

Open-loop system

It designates the process to be controlled. It comprises a control signal, which can be imposed, and a signal to be regulated, which is measured. The aim of control is to bring the measurement to reach an imposed setpoint by acting on the control signal.

Closed-loop system

It designates the regulated process. It comprises a corrector and an open-loop system. The closed-loop system is given a setpoint, and the measurement must become equal to the setpoint.

PID corrector

This is the part of the closed-loop system that calculates the control of the open-loop system from the deviation between the setpoint and the measurement of the closed-loop system. In the case of the PID corrector, the control signal is obtained by adding three terms. One is proportional to this deviation (setpoint – measurement), the second is proportional to the integral of the...