ABB ACS 800 Series, Firmware Manual

Page: 301 / 340

Adaptive Programming examples for crane control
301
Brake match
Brake match detects mechanical brake slips and downward movement of the load
when Mechanical brake control is in use, the operator has given the stop command
and the target is to close the brake. The slip detection is based on the motor encoder
position signal, and the function works only if an encoder is used. You can use the
function for an automatic restart of the crane or just for a warning (alarm) indication.
Working logic
The logic checks whether the motor is rotating when the mechanical brake should be
closed. The rotation is detected by comparing two successive position signal
samples (
02.21 POS ACT PPU). Therefore, the system needs to be equipped with a
pulse encoder. The logic works during the normal Stop command, extended run
time, and also, when the drive is in the standby (spare unit) mode.
If the position differs between the two successive samples more than set with
parameter
85.01 CONSTANT1, and the motor torque is less than the preset value,
Brake match is activated. By means of pointer parameter 97.21 ZERO SPEED PTR,
the drive will start with a zero speed reference, and a brake match warning is shown
on the control panel and in the fault logger. You can reset the warning by giving a
new start command: DI1 forward or DI2 reverse. While brake match is active, the
mechanical brake open command is prevented.
For Brake match to work, you need to connect the output of AP block number 10 to
hidden parameter
97.21 ZERO SPEED PTR. You can open group 97 by entering
pass code 5600 into parameter 16.03 PASS CODE.
The following figures present an example AP file solution for Brake match.
Note: When creating the actual AP files, you must be pay attention to safety issues
and carefully check the logic case by case.