ABB ACS280, Firmware Manual, Page: 65 / 430

Program features 65
Frequency trim connection
Frequency trim is added at 28.02 Frequency ref ramp out and the final frequency
reference is generated after the trim addition. At the moment, no parameter is
available to see the final frequency reference after adding frequency trim.
Note : PID trim output auto connection is disabled in the firmware when the
drive is stopped with the
21.04 Emergency stop mode
value
Ramp stop (Off1)
or
value
Eme ramp stop (Off3)
. In other words, PID trim output actual (
40.05
Process PID trim output act
) will not be added to the respective speed, torque
and frequency reference chains during ramp stop or emergency stop.

Mechanical brake control
A mechanical brake can be used for holding the motor and driven machinery at
zero speed when the drive is stopped, or not powered. The brake control logic
observes the settings of parameter group
44 Mechanical brake control
as well
as several external signals, and moves between the states presented in the
diagram on page
66
. The tables below the state diagram detail the states and
transitions. The timing diagram on page
67
shows an example of a close-open-
close sequence.
Inputs of the brake control logic
The start command of the drive (bit 5 of
06.16 Drive status word 1
) is the main
control source of the brake control logic.
Outputs of the brake control logic
The mechanical brake is controlled by bit 0 of parameter
44.01 Brake control
status
. This bit should be selected as the source of a relay output (or a digital
output) which is then wired to the brake actuator through a relay. See the wiring
example on page
68
.
The brake control logic, in various states, will request the drive control logic to
hold the motor, or ramp down the speed. These requests are visible in
parameter
44.01 Brake control status
.
28.02 Frequency ref ramp out
Frequency trim
Final frequency
+