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3 Parameter Description
21-21 Ext. 1 Proportional Gain
Range:
0.01 N/A*
[0.00 - 10.00 N/A]
If (Error x Gain) jumps with a value equal to what is set in par.20-14
equal to what is set in par. 4-13/4-14, Motor Speed High Limit, but in practice of course limited by this setting.
The proportional band (error causing output to change from 0%–100%) can be calculated by means of the formula:
3
(
)
1
× (
Proportional Gain
NOTE!
Always set the desired for par.20-14
21-22 Ext. 1 Integral Time
Range:
10000.00
[0.01 - 10000.00 s]
s*
21-23 Ext. 1 Differentation Time
Range:
0.00 s*
[0.00 - 10.00 s]
21-24 Ext. 1 Dif. Gain Limit
Range:
5.0 N/A*
[1.0 - 50.0 N/A]
3-188
Function:
The proportional gain indicates the number of times the error between the setpoint and the feedback
signal is to be applied.
)
Max Reference
Maximum Reference/Feedb.
Function:
Over time, the integrator accumulates a contribution to the output from the PID controller as long
as there is a deviation between the reference/setpoint and feedback signals. The contribution is
proportional to the size of the deviation. This ensures that the deviation (error) approaches zero.
Quick response on any deviation is obtained when the integral time is set to a low value. Setting it
too low, however, may cause the control to become unstable.
The value set is the time needed for the integrator to add the same contribution as the proportional
part for a certain deviation.
If the value is set to 10,000, the controller will act as a pure proportional controller with a P-band
based on the value set in par.20-93
from the proportional controller will be 0.
Function:
The differentiator does not react to a constant error. It only provides a gain when the feedback
changes. The quicker the feedback changes, the stronger the gain from the differentiator.
Function:
Set a limit for the differentiator gain (DG). The DG will increase if there are fast changes. Limit the
DG to obtain a pure differentiator gain at slow changes and a constant differentiator gain where
quick changes occur.
MG.11.C6.22 - VLT
Maximum Reference/Feedb.
, the PID controller will try to change the output speed
before setting the values for the PID controller in par. group 20-9*.
PID Proportional Gain
®
is a registered Danfoss trademark
VLT
®
HVAC Drive Programming Guide
. When no deviation is present, the output
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