User's Manual

Automation and Drives - SCE
T I A Training Document Page 24 of 64 Module
2.7.3.2 Integral Action Controllers (I- Controller)
Integrating controllers are used to completely correct system deviations at every operating point. As
long as the system deviation is not equal to zero, the amount of the controller output changes. Only
when the reference variable and the controlled variable are equal -at the latest however, when the
controller output reaches its system-dependent limit (Umax, Pmax etc.)- is the controller in a steady
state.
The mathematical formula for this integral action is:
The controller output is proportional to the time integral of the system deviation:
with
How fast the controller output rises (or falls), depends on the system deviation and the integration
time.
Block Diagram
Preface Fundamentals Discontinuous Action Controller Controller Block (S)FB41 Setting the System Appendix
B3
Issued: 02/2008 Control Engineering with STEP 7