ABB ACS850 series, Firmware Manual

Page: 131 / 260

Parameters 131
23.05 Acc comp DerTime Defines the derivation time for acceleration/(deceleration)
compensation. In order to compensate inertia during
acceleration, a derivative of the reference is added to the
output of the speed controller. The principle of a derivative
action is described for parameter
23.03 Derivation time .
Note: As a general rule, set this parameter to the value
between 50 and 100% of the sum of the mechanical time
constants of the motor and the driven machine.
The figure below shows the speed responses when a high
inertia load is accelerated along a ramp.
No acceleration compensation:
Acceleration compensation:
0.00 … 600.00 s Acceleration compensation derivation time. 100 = 1 s
23.06 Acc comp Ftime Defines the derivation filter time constant for the
acceleration(/deceleration) compensation. See parameters
23.03 Derivation time and 23.05 Acc comp DerTime .
0.0 … 1000.0 ms Derivation filter time constant for acceleration compensation. 10 = 1 ms
23.07 Speed err Ftime Defines the time constant of the speed error low pass filter.
If the used speed reference changes rapidly (like in a servo
application), the possible interferences in the speed
measurement can be filtered with the speed error filter.
Reducing the ripple with filter may cause speed controller
tuning problems. A long filter time constant and fast
acceleration time contradict one another. A very long filter
time results in unstable control.
0.0 … 1000.0 ms Speed error filtering time constant. 0 = filtering disabled. 10 = 1 ms
No. Name/Value Description FbEq
Time
%
Speed reference
Actual speed
Time
%
Speed reference
Actual speed