ABB ACSM1 Manual page 53

The figure below shows speed responses at a speed reference step (typically
1...20%).
n
%
n
N
A
A: Undercompensated
B: Normally tuned (autotuning)
C: Normally tuned (manually). Better dynamic performance than with B
D: Overcompensated speed controller
The figure below is a simplified block diagram of the speed controller. The controller
output is the reference for the torque controller.
Speed
+ Error
-
reference
value
Actual speed
For more information on the use of the autotune function, see the description of
parameter 28.16 PI TUNE
C
B
Derivative
acceleration
compensation
Proportional,
integral
Derivative
MODE.
D
t
+
Torque
+
reference
+
Drive control and features
53