Mitsubishi Electric Melservo MR-J3-A Instruction Manual page 444

14. ABSOLUTE POSITION DETECTION SYSTEM
(2) Transfer method
The sequence in which the base circuit is turned ON (servo-on) when it is in the OFF state due to the
servo-on (SON) going OFF, an emergency stop, or alarm, is explained below. In the absolute position
detection system, always give the serial communication command to read the current position in the servo
amplifier to the controller every time the ready (RD) turns on. The servo amplifier sends the current position
to the controller on receipt of the command. At the same time, this data is set as a position command value
in the servo amplifier.
(a) Sequence processing at power-on
Power
supply
Servo-on
(SON)
Base
circuit
Ready
(RD)
Absolute position data
command transmission
Absolute position data
receive
Current position
Pulse train command
1) 95ms after the servo-on (SON) has turned on, the base circuit turns on.
2) After the base circuit has turned on, the ready (RD) turns on.
3) After the ready (RD) turned on and the controller acquired the absolute position data, give command
pulses to the drive unit. Providing command pulses before the acquisition of the absolute position
data can cause a position shift.
(b) Communication error
If a communication error occurs between the controller and servo amplifier, the servo amplifier sends
the error code. The definition of the error code is the same as that of the communication function. Refer
to section 13.3.3 for details.
If a communication error has occurred, perform retry operation. If several retries do not result in a
normal termination, perform error processing.
ON
OFF
ON
OFF
80ms
ON
OFF
ON
OFF
During this period, get absolute position data.
14 - 59
5ms
ABS data
Current position change