ABB ACSM1 Firmware Manual page 145

26.08 ACC COMP DERTIME
Defines the derivation time for acceleration (deceleration) compensation. Used to improve the speed
control dynamic reference change.
In order to compensate inertia during acceleration, a derivative of the speed reference is added to the
output of the speed controller. The principle of a derivative action is described for parameter
DERIVATION TIME.
Note: The parameter value should be proportional to the total inertia of the load and motor,
i.e. approximately 50...100% of the mechanical time constant (t
constant equation in parameter
If parameter value is set to zero, the function is deactivated.
The figure below shows the speed responses when a high inertia load is accelerated along a ramp.
No acceleration compensation
Speed reference
%
Actual speed
See also parameter
The source for the acceleration compensation torque can also be selected by parameter
COMPENSATION. See firmware group
0...600 s
26.09 ACC COMP FTIME
Defines the filter time for the acceleration compensation.
0...1000 ms
26.10 SPEED WIN FUNC
Enables or disables speed error window control.
Speed error window control forms a speed supervision function for a torque-controlled drive. It
supervises the speed error value (speed reference – actual speed). In the normal operating range,
window control keeps the speed controller input at zero. When the speed error moves outside the
window, the exceeding part of the error value is connected to the speed controller. The speed
controller produces a reference term relative to the input and gain of the speed controller (parameter
28.02 PROPORT
the internal torque reference for the drive.
Example: In a load loss condition, the internal torque reference of the drive is decreased to prevent an
excessive rise of the motor speed. If window control were inactive, the motor speed would rise until a
speed limit of the drive were reached.
(0) DISABLED
(1) ABSOLUTE
FW block: SPEED ERROR
22.02 SPEED ACT
t
26.09 ACC COMP FTIME.
28 SPEED CONTROL.
Derivation time for acceleration/deceleration compensation.
FW block: SPEED ERROR
Filter time for acceleration compensation. 0 ms = filtering disabled.
FW block: SPEED ERROR
GAIN) which the torque selector adds to the torque reference. The result is used as
Speed error window control inactive.
Speed error window control active. The window boundaries set by
parameters
(the boundaries have a negative value when actual speed is
negative).
(see above)
). See the mechanical time
mech
FTIME.
No acceleration compensation
%
(see above)
(see above)
28.02 and 28.02 are effective in both directions of rotation
Parameters and firmware blocks
145
28.04
t
28.06 ACC