Rockwell Automation 284 ArmorStart User Manual - Manual (Page 472)

I-6 PID Setup
3. At this point, the differential gain may not be needed. However, if
after determining the values for Parameter 234 (PID Prop Gain)
and Parameter 235 (PID Integ Time):
• Response is still slow after a step change, increase Parameter
236 (PID Diff Rate).
• Response is still unstable, decrease Parameter 236 (PID Diff
Rate).
The following figures show some typical responses of the PID loop at
different points during adjustment of the PID Gains.
Figure I.1 Unstable
Figure I.2 Slow Response — Over-Damped
Figure I.3 Oscillation — Under-Damped
Figure I.4 Good Response — Critically Damped
PID Feedback
PID Reference
Time
PID Feedback
PID Reference
Time
PID Feedback
PID Reference
Time
PID Feedback
PID Reference
Time