Lite-On Technology Corp.
Industrial Automation
190
PC-22
BTCD
Turn-off delay time for the
electromagnetic brake
Communication
address:
022CH
022DH
Initial value
0
Control mode
ALL
Unit
ms
Configuration range
-1000 ~ 1000
Data size
16bit
Data format
Dec
Parameter function: It sets the time delayed from the the time servo is ready and turned off to
the time that the interlock signal of the electromagnetic brake (DO code 0x07, BREAK) is
turned off. (Refer to 7.5.4 for the use of the electromagnetic brake.)
1) When the BTCD delay time is not over and the motor rotation speed is below the one for PC-20, the
interlock signal of the electromagnetic brake (BREAK) is turned off.
2) When the BTCD delay time is over and the motor rotation speed is above the one for PC-20, the interlock
signal of the electromagnetic brake (BREAK) is turned off.
3) If the Alarm or EMGS occurs causes the servo to be turned off, the negative value of BTCD will not become
effective if a negative value is assigned to BTCD. This is equivalent to the situation that BVCD is set to zero.
7.5.5.
Use of the electromagnetic brake
For the electromagnetic brake by the drive, (1)
BREAK
is set to OFF. In this case, the electromagnetic
brake is inoperative and the motor is under the machinery lockout condition. (2) BREAK is set to ON. In
that case, the electromagnetic brake is in operation and the motor rotates freely. The operation of
electromagnetic brake can be divided into two types below. The user uses the parameter BTOD (PC-21)
and BTCD (PC-22) to set relevant delay. Usually the electromagnetic brake is used for Z-axis direction to
prevent high quantity of heat generated by high resistance created continuously by the servo motor. Such
heat would cause the shortening of motor lifetime. For this device, the electromagnetic motor can only be
activated after the servo is off to avoid malfunctions. In the situation that the electromagnetic brake is
manipulated by the user, it can only be activated during braking. Therefore the braking force of the
electromagnetic brake and the motor would be in the same direction. The drive operation becomes normal
because it is less likely to require the intervention from the braking force of the electromagnetic brake.
During acceleration or deceleration, the drive generates higher current to overcome the braking force of
the electromagnetic brake. The alarm for overload protection could be triggered.
Time diagram of the control on electromagnetic brake: