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Absolute position detection system – MITSUBISHI ELECTRIC MELSERVO MR-J2S- A User Manual

Page 322

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15 - 15

15. ABSOLUTE POSITION DETECTION SYSTEM

(4) At the time of emergency stop reset

(a) If the power is switched ON in the emergency stop state

The emergency stop state can be reset while the ABS data is being transferred.
If the emergency stop state is reset while the ABS data is transmitted, the base circuit is turned
ON 80[ms] after resetting. If the ABS transfer mode (ABSM) is OFF when the base circuit is
turned ON, the ready (RD) is turned ON 20[ms] after the turning ON of the base circuit. If the ABS
transfer mode (ABSM) is ON when the base circuit is turned ON, it is turned OFF and then the
ready (RD) is turned ON. The ABS data can be transmitted after the emergency stop state is reset.
The current position in the servo amplifier is updated even during an emergency stop. When servo-
on (SON) and ABS transfer mode (ABSM) are turned ON during an emergency stop as shown
below, the servo amplifier transmits to the controller the current position latched when the ABS
transfer mode (ABSM) switches from OFF to ON, and at the same time, the servo amplifier sets
this data as a position command value. However, since the base circuit is OFF during an
emergency stop, the servo-lock status is not encountered. Therefore, if the servo motor is rotated by
external force or the like after the ABS transfer mode (ABSM) is turned ON, this travel is
accumulated in the servo amplifier as droop pulses. If the emergency stop is cleared in this status,
the base circuit turns ON and the motor returns to the original position rapidly to compensate for
the droop pulses. To avoid this status, reread the ABS data before clearing the emergency stop.

OFF

ON

OFF

ON

OFF

ON

OFF

ON

OFF

ON

OFF

ON

OFF

ON

80[ms]

OFF

ON

20[ms]

Power
supply

Servo-on
(SON)

Emergency stop
(EMG)

ABS transfer mode
(ABSM)

ABS request
(ABSR)

Send data ready
(TLC)

Send (ABS) data

Base circuit

Ready
(RD)

Reset

During transfer of ABS

ABS data

Operation

enabled