B&R ACOPOSinverter P84, User Manual

Page: 249 / 405

Programming guidelines
ACOPOSinverter P84 User's Manual 2.10 249
What results in a falling ramp (with reversing direction) with proportional gain and a continually positive
error?
This needs to be studied.
siRPEInternal
Signed
Scaling Zero
Dec
siSpdEstEnt
Signed
Scaling Zero
Dec
siPIDQ13_ref
Signed
Scaling Zero
Dec
siRPEInternal = PID fault
siSpdEstEnt = Motor speed
siPIDQ13_ref = PID output
CMD bit 8 = 0
Drive starts
CMD bit 8 = 1
Drive stops
Position reference moves
CMD bit 8 = 0
High RPG value, the PID
output responds quickly. Even if the
error is slowly reduced,
the PID output goes in reverse.
The error is positive, and the PID feedback
does not have time to reach the position.
Why does this PID output go in reverse?
PID error slowly
decreases but stays positive
In the case of a high RPG-value the PID output responds more rapidly. This PID output is even reversed in the
case of a positive fault. The PID Feedback does not have enough time to reach the PID reference variable, but the
inverter turns round. In practical use, this means that this position is never reached.
The behavior is also similar to when the inverter is in RUN mode and the PID reference variable changes.