ABB ACS880 Firmware Manual page 87

Autotune modes
Autotuning can be performed in three different ways depending on the setting of
parameter 25.34 Speed controller autotune
and Tight define how the drive torque reference should react to a speed reference
step after tuning. The selection
produces a fast response but possibly too high gain values for some applications.
The figure below shows speed responses at a speed reference step (typically
1...20%).
n
%
n
N
A
A: Under compensated
B: Normally tuned (autotuning)
C: Normally tuned (manually). Better dynamic performance than with B
D: Over compensated speed controller
Autotune results
At the end of a successful autotune routine, its results are automatically transferred
into parameters
• 25.02 Speed proportional gain
• 25.03 Speed integration time
• 25.37 Mechanical time constant
machine).
Nevertheless, it is still possible to manually adjust the controller gain, integration time
and derivation time.
mode. The selections Smooth,
Smooth produces a slow but robust response;
B
(proportional gain of the speed controller)
(integration time of the speed controller)
(mechanical time constant of the motor and
Standard program features 87
C D
Normal
Tight
t