Communication-Based Abs Transfer System; Serial Communication Command; Absolute Position Data Transfer Protocol - Mitsubishi Electric Melservo MR-J3-A Instruction Manual

14. ABSOLUTE POSITION DETECTION SYSTEM

14.10 Communication-based ABS transfer system

14.10.1 Serial communication command

The following commands are available for reading absolute position data using the serial communication
function. When reading data, take care to specify the correct station number of the drive unit from where the
data will be read.
When the master station sends the data No. to the slave station (servo amplifier), the slave station returns the
data value to the master station.
(1) Transmission
Transmit command [0][2] and data No. [9][1].
(2) Reply
The absolute position data in the command pulse unit is returned in hexadecimal.
Data 32-bit length (hexadecimal representation)

14.10.2 Absolute position data transfer protocol

(1) Data transfer procedure
Every time the servo-on (SON) turns on at power-on or like, the controller must read the current position
data in the servo amplifier. Not performing this operation will cause a position shift.
Time-out monitoring is performed by the controller.
Servo amplifier
Command [0][2]
Absolute position
data acquisition
Absolute position data return
SON ON
RD ON
Absolute position data
command transmission
data No.[9][1]
Position command start
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Controller
Watch dog timer
Current position
acquisition
Current value
change