ABB ACS355 series User Manual page 238

238 Actual signals and parameters
All parameters
No. Name/Value
2303 DERIVATION
TIME
0....10000 ms
Description
Defines the derivation time for 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.
The figure below shows the speed controller output after an
error step when the error remains constant.
Δe
K · T ·
p D
T
K · e
s
p
K · e
p
Gain = K = 1
p
T = Integration time > 0
I
T = Derivation time > 0
D
T = Sample time period = 2 ms
s
Δe = Error value change between two samples
Time
%
e = Error value
T
I
Def/FbEq
0 ms
Controller
output
Error value
t
1 = 1 ms