ABB ACS560 Firmware Manual page 232

232 Parameters
No. Name/Value
25.04 Speed derivation
time
e
K × T ×
p D
T
s
0.000...10.000 s
25.05 Derivation filter time
0...10000 ms
Description
Defines the derivation time of the speed controller. Derivative
action boosts the controller output if the error value changes.
The longer the derivation time, the more the speed controller
output is boosted during the change. If the derivation time is
set to zero, the controller works as a PI controller, otherwise
as a PID controller. The derivation makes the control more
responsive for disturbances. For simple applications,
derivative time is not normally required and should be left at
zero.
The speed error derivative must be filtered with a low pass
filter to eliminate disturbances.
The figure below shows the speed controller output after an
error step when the error remains constant.
%
K × e
p
K × e
p
Gain = K = 1
p
T = Integration time > 0
I
T = Derivation time > 0
D
T = Sample time period = 250 µs
s
e = Error value change between two samples
Derivation time for speed controller.
Defines the derivation filter time constant. See parameter
25.04 Speed derivation
Derivation filter time constant.
Controller output
Error value
Time
T
I
time.
Def/FbEq16
0.000
e = Error value
1000 = 1
8
1 = 1