ABB ACS280 Firmware Manual page 162

162 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 (especially those without a pulse
encoder), 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
25.04 Speed derivation time
parameter
Derivation filter time constant.
Controller output
Error value
Time
T
I
.
Default
FbEq 16
0.000 s
e = Error value
1000 = 1 s
8 ms
1 = 1 ms