20-95 PID Differentiation Time
Range:
Function:
0.00
s
*
[0.00 -
10.00 s]
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 response 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
difficult to adjust this for proper system control.
Differentiation time is not commonly used in VLT
HVAC Drive applications. Therefore, it is generally
best to leave this parameter at 0 or OFF.
20-96 PID Diff. Gain Limit
Range:
Function:
5.0
*
[1.0 -
50.0 ]
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 reduces the maximum effect of the
PID Controller’s differential function.
This parameter is only active when
is not set to OFF (0 s).
Parameter Description
VLT
®
HVAC Drive Programming Guide
132
MG.11.CB.02 - VLT
®
is a registered Danfoss trademark
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