Mitsubishi Electric MELSERVO MR-J3 A Series, Instruction Manual

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14 - 10
14. ABSOLUTE POSITION DETECTION SYSTEM
(b) Detailed description of absolute position data transfer
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
3)
4)
5)
7)
(Note)
1)
2) 6)
Servo-on
(programmable
controller)
Servo-on
(SON)
ABS transfer mode
(ABSM)
ABS request
(ABSR)
ABS transmission
data ready
(ABST)
Transmission (ABS) data
During transfer of ABS
Lower
2 bits
Check sum
Upper 2 bits
Note. If the servo-on (SON) is not turned ON within 1 second after the ABS transfer mode (ABSM) is turned ON, an SON
time-out warning (AL.EA) occurs. This warning, however, does not interrupt data transmission.
It is automatically cleared when the servo-on (SON) is turned ON.
1) The programmable controller turns ON the ABS transfer mode (ABSM) and servo-on (SON) at the
leading edge of the internal servo-on (SON).
2) In response to the ABS transfer mode (ABSM), the servo detects and calculates the absolute position
and turns ON the ABS transmission data ready (ABST) to notify the programmable controller that the
servo is ready for data transmission.
3) After acknowledging that the ready to send (ABST) has been turned ON, the programmable controller
turns ABS request (ABSR) ON.
4) In response to ABS request (ABSR), the servo outputs the lower 2 bits of the ABS data and the ABS
transmission data ready (ABST) in the OFF state.
5) After acknowledging that the ABS transmission data ready (ABST) has been turned OFF, which
implies that 2 bits of the ABS data have been transmitted, the programmable controller reads the
lower 2 bits of the ABS data and then turns OFF the ABS request (ABSR).
6) The servo turns ON the ABS transmission data ready (ABST) so that it can respond to the next
request.
Steps 3) to 6) are repeated until 32-bit data and the 6-bit check sum have been transmitted.
7) After receiving of the check sum, the programmable controller turns the ABS transfer mode (ABSM)
OFF.
If the ABS transfer mode (ABSM) is turned OFF during data transmission, the ABS transfer mode
(ABSM) is interrupted.