ABB ACSM1 - Page 170

Parameters and firmware blocks
170
28.04 DERIVATION TIME FW block: SPEED CONTROL (see above)
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.
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.
Note: Changing this parameter value is recommended only if a pulse encoder is used.
0…10 s Derivation time for speed controller.
28.05 DERIV FILT TIME FW block: SPEED CONTROL (see above)
Defines the derivation filter time constant.
0…1000 ms Derivation filter time constant.
28.06 ACC COMPENSATION FW block: SPEED CONTROL (see above)
Selects the source for the acceleration compensation torque.
The default value is P.3.7, ie, signal 3.07 ACC COMP TORQ, which is the output of the SPEED
ERROR firmware block.
Note: This parameter has been locked, ie, no user setting is possible.
Value pointer: Group and index
T
I
t
%
Gain = K
p
= 1
T
I
= Integration time > 0
T
D
= Derivation time > 0
T
s
= Sample time period = 250 µs
e = Error value
Δe = Error value change between two samples
K
p
× T
D
×
Δe
T
s
Controller output
Error value
K
p
×e
K
p
×e
e = Error value