Control Action With Different Feedback Structures - Siemens SIMATIC S5 Manual

4.3 Control Action with Different Feedback Structures

To achieve accurate control and optimum correction of the disturbance variable, the controller must
be tuned to the dynamic response of the controlled system.
To do this, feedback structures are used which have a proportional action (P), proportional plus
derivative action (PD), proportional pus integral action (PI) or proportional plus integral plus
derivative action (PID), depending on the structure of the feedback circuit. If there is a sudden step
at the controller input, the response is also in the form of a step as shown in the following diagrams,
assuming that the delay times of the controller are negligible and that the controller reacts very
quickly.
P controller
IP244
C79000–B8576–C860–02
Notes on Controller Settings
4–127