ABB ACS860, Firmware Manual

Page: 172 / 438

172 Parameters
25.08 Drooping rate Defines the droop rate in percent of the nominal motor speed.
Drooping decreases the drive speed slightly as the drive load
increases. The actual speed decrease at a certain operating
point depends on the droop rate setting and the drive load (=
torque reference / speed controller output). At 100% speed
controller output, drooping is at its nominal level, i.e. equal to
the value of this parameter. The drooping effect decreases
linearly to zero along with the decreasing load.
The droop rate can be used e.g. to adjust the load sharing in a
Master/Follower application run by several drives. In a
Master/Follower application the motor shafts are coupled to
each other.
The correct droop rate for a process must be found out case
by case in practice. 0.00%
0.00 … 100.00% Droop rate. 100 = 1%
25.09 Speed ctrl
balancing enable Selects the source for enabling/disabling speed controller
output balancing.
This function is used to generate a smooth, “bumpless”
transfer from a torque- or tension-controlled motor back to
being speed-controlled. When balancing is enabled, the
output of the speed controller is forced to the value of
25.10
Speed ctrl balancing ref .
Balancing is also possible in the ramp generator (see
parameter
23.26 Ramp out balancing enable ).
0 = Disabled
1 = Enabled
Not selected
Not selected 0. 1
Selected 1. 2
DI1 Digital input DI1 ( 10.02 DI delayed status , bit 0). 2
DI2 Digital input DI2 ( 10.02 DI delayed status , bit 1). 3
DI3 Digital input DI3 ( 10.02 DI delayed status , bit 2). 4
DI4 Digital input DI4 ( 10.02 DI delayed status , bit 3). 5
DI5 Digital input DI5 ( 10.02 DI delayed status , bit 4). 6
No. Name/Value Description Def / FbEq16
Motor speed in
% of nominal
100%
Speed decrease = Speed controller output × Drooping × Nominal speed
Example: Speed controller output is 50%, droop rate is 1%, nominal speed of the drive is
1500 rpm.
Speed decrease = 0.50 × 0.01 × 1500 rpm = 7.5 rpm.
100%
25.08 Drooping rate
No drooping
Drooping
Speed controller
output / %
Drive load