A solution for the study and understanding of PID controllers

Today, in most automatic process control applications in industry are used PID controllers. It is very important for the students to understand how work these controllers and how important it is to make an optimal tuning of these controllers. This paper presents a solution which permits to study and understand PID controllers. This solution is a closed-loop speed control system in a centrifugal load application which permits air flow control by fan´s motor speed adjusts using a VFD. The PID controller is implemented in a PLC that control the VFD by CANOpen protocol.