Siemens SIMATIC Manual page 47

Overshoot
Overshoot can occur in the following situations:
Situation
End of tuning
Tuning in
Phase 7
Control mode
PID Temperature Control
A5E00125039-02
Cause
•
Excitation by a manipulated
variable change too high
compared with the setpoint step
change (see above).
•
PI controller activated by
PID_ON = FALSE.
Initially, less aggressive controller
parameters are obtained (process
type III) that can lead to overshoot in
Phase 7.
PI controller and with
PFAC_SP = 1.0 for process type I.
Controller Tuning in FB 58 "TCONT_CP"
Remedy
•
Increase the setpoint step
change or reduce the
manipulated variable step
change.
•
If the process permits a PID
controller, start the tuning with
PID_ON = TRUE.
-
If the process permits a PID
controller, start the tuning with
PID_ON = TRUE.
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