Trane TR200 Series Programming Manual page 199

Parameter Description
20-95 PID Differentiation Time
Range:
0.00 s* [0.00 - 10.00 s]
20-96 PID Diff. Gain Limit
Range:
5.0 N/A* [1.0 - 50.0 N/A]
198
Function:
The differentiator monitors the rate of change of the feedback. If the
feedback is changing quickly, it will adjust the output of the PID Controller
to reduce the rate of change of the feedback. Quick PID Controller re-
sponse is obtained when this value is large. However, if too large of a
value is used, the frequency converter's output frequency may become
unstable.
Differentiation time is useful is situations where extremely fast frequency
converter response and precise speed control are required. It can be dif-
ficult to adjust this for proper system control. Differentiation time is not
commonly used in TR200 applications. Therefore, it is generally best to
leave this parameter at 0 or OFF.
Function:
The differential function of a PID Controller responds to the rate of
change of the feedback. As a result, an abrupt change in the feedback
can cause the differential function to make a very large change in the PID
Controller's output. This parameter limits the maximum effect that the
PID Controller's differential function can produce. A smaller value re-
duces the maximum effect of the PID Controller's differential function.
This parameter is only active when par.20-95
not set to OFF (0 s).
PID Differentiation Time is
TR200 Programming Guide