Vexta aStep AS Series Operating Manual page 41

Operating the electromagnetic brake
Operate the electromagnetic brake as follows:
1.
ALARM output is in the "OFF" state immediately after the driver power is turned on.
Check to see that ALARM output has been reset (turned from OFF to ON), then turn on the
electromagnetic brake.
2.
Before inputting pulse signals to operate the motor, set the motor in the ready state by
"releasing" the electromagnetic brake.
3.
To allow the electromagnetic brake to "hold" the load after the motor has completed its
operation, turn the electromagnetic brake off only after verifying that END (positioning
complete) output has turned from "OFF" to "ON."
Driver power
ALARM output
Electromagnetic brake power
CW pulse input or CCW pulse input ∗
END output
∗CCW pulse input is enabled when 2-pulse input mode is selected
About providing for ALARM output
When the driver-protection function is triggered, the motor stops as the current is turned off.
The motor loses its holding ability, which in a vertical-travel application may cause the load to
fall.
The user must set a controller sequence that will cut off the power to the electromagnetic brake
and hold the load in position upon detecting an "OFF" ALARM output.
Backlash of the electromagnetic brake
There is a backlash between the electromagnetic brake and motor shaft, but it is structurally
necessary.
When the driver power comes back on, the position of the motor's output shaft may differ from
the previous position, even though the position has been maintained by the electromagnetic
brake.
For that reason, after power-on be sure to detect the equipment's home position before
resuming operation.
ON
OFF
0.5 s maximum
0 s minimum
ON
OFF
ON
Brake releasing
OFF
0.1 s minimum
ON
OFF
ON
OFF
When operation is started
0.5 s minimum
0.1 s minimum
When operation is stopped
Note
To hold the load in position, apply
the electromagnetic brake only
after the motor has stopped. Do
not use the brake to bring the
moving motor to a halt.
Repeated braking for such a
purpose will wear the brake hub
excessively, causing a decrease
in its ability to hold.
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