The proportional band (error causing output to change
from 0–100%) can be calculated with the formula
1
Proportional Gain × Max Reference
21-22 Ext. 1 Integral Time
Range:
Function:
10000
s
*
[0.01 -
10000 s]
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 propor-
tional 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 for a certain deviation.
If the value is set to 10000, the controller
acts as a pure proportional controller with a
P-band based on the value set in
parameter 20-93 PID Proportional Gain
. When
no deviation is present, the output from the
proportional controller is 0.
21-23 Ext. 1 Differentation Time
Range:
Function:
0 s
*
[0 - 10 s] 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.
21-24 Ext. 1 Dif. Gain Limit
Range:
Function:
5
*
[1 - 50 ] Set a limit for the differentiator gain (DG). The DG
increases 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.
3.19.4 21-3* Closed Loop 2 Ref/Fb
21-30 Ext. 2 Ref./Feedback Unit
Option:
Function:
See
parameter 21-10 Ext. 1 Ref./Feedback Unit
for
details.
[0]
None
[1]
*
%
[5]
PPM
[10]
1/min
[11]
RPM
21-30 Ext. 2 Ref./Feedback Unit
Option:
Function:
[12]
Pulse/s
[20]
l/s
[21]
l/min
[22]
l/h
[23]
m³/s
[24]
m³/min
[25]
m³/h
[30]
kg/s
[31]
kg/min
[32]
kg/h
[33]
t/min
[34]
t/h
[40]
m/s
[41]
m/min
[45]
m
[60]
°C
[70]
mbar
[71]
bar
[72]
Pa
[73]
kPa
[74]
m WG
[75]
mm Hg
[80]
kW
[120] GPM
[121] gal/s
[122] gal/min
[123] gal/h
[124] CFM
[125] ft³/s
[126] ft³/min
[127] ft³/h
[130] lb/s
[131] lb/min
[132] lb/h
[140] ft/s
[141] ft/min
[145] ft
[160] °F
[170] psi
[171] lb/in²
[172] in WG
[173] ft WG
[174] in Hg
[180] HP
21-31 Ext. 2 Minimum Reference
Range:
Function:
0 ExtPID2Unit
*
[ -999999.999 -
par. 21-32
ExtPID2Unit]
See
for
details.
Parameter Descriptions
Programming Guide
MG11CE02
Danfoss A/S © 03/2015 All rights reserved.
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