Mitsubishi Electric MELSERVO-J5 User Manual page 303

• Detailed explanation of absolute position data transfer
Servo-on in programmable controller
SON (Servo-on)
ABSM (ABS transfer mode)
ABSR (ABS request)
ABST (ABS transmission data ready)
ABSB0 (ABS transmission data bit 0)
ABSB1 (ABS transmission data bit 1)
*1 If SON does not turn on within 1 s after ABSM on, [AL. 0EA ABS servo-on warning] will occur. However, the alarm will not influence the
transfer. SON on will cancel [AL. 0EA] automatically.
The programmable controller turns on ABSM and SON at the rising edge of the internal servo-on. (1)
In response to the ABS transfer mode, the servo detects the absolute value, calculates the absolute position, then turns on
ABST to notify the programmable controller that the servo is ready for data transmission. (2)
After recognizing that ABST has turned on, the programmable controller will turn on ABSR. (3)
In response to ABSR, the servo outputs the lower 2 bits of ABS and turns off ABST. (4)
The programmable controllers recognizes that the ABST has turned off (ABS 2 bits data have been outputted), reads the
lower 2 bits of ABST and turns off ABSR. (5)
The servo turns on ABST to respond to the next request. Step (3) to (6) are repeated until 32-bit data and the 6-bit checksum
have been transmitted. (6)
After receiving of the checksum, the programmable controller confirms that the 19th ABST is turned on, and then turns off
ABSM. If ABSM is turned off during data transmission, the ABS transfer mode is interrupted and [AL. 0E5] occurs. (7)
ON
OFF
ON
OFF
*1
(1)
ON
OFF
(3) (5)
ON
OFF
(2) (4) (6)
ON
OFF
1
Lower 2
bits
During ABS transfer
2 18
7 ABSOLUTE POSITION DETECTION SYSTEM
7.3 Absolute position detection system by DIO [A]
(7)
19
Upper 2 bits of
checksum
7
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