Mitsubishi A1SD75M1, User Manual

Page: 342 / 746

8 - 8
MELSEC-A
8 ZERO POINT RETURN CONTROL
Restrictions
The system where the zero point can always be passed between a machine zero
point return start and the near-point dog ON to OFF, is required.
Precautions during operation
(1) An error "Start at zero point" (error code: 201) will occur if another machine
zero point return is attempted after a machine zero point return completion
when the zero point return retry function is not set ("0" is set in " Pr.50 Zero
point return retry").
(2) Machine zero point returns carried out from the near-point dog ON position will
start at the " Pr.49 Creep speed".
(3) The near-point dog must be ON during deceleration from the zero point return
speed " Pr.49 Creep speed".
(4) If the zero point has never been passed between a machine zero point return
start and the near-point dog ON to OFF, an error "zero point not pass at zero
point return" (error code: 210) occurs, resulting in deceleration to a stop.
In the system where the distance between the machine zero point return
starting position and zero point is too short to pass the zero point, select the
zero point return method (2): "near-point dog method 2)".
Pr. 49 Creep speed
t
V
ON
OFF
ON
OFF
OFF
ON
OFF
Zero point
Pr. 48 Zero point return speed
Near-point
dog
Machine zero point return start
(Positioning start signal)
Zero point return request flag
[ Md.40 Status : b3]
Zero point return complete flag
[ Md.40 Status : b4]
Md.35 Axis operation status
Md.44 Movement amount
after near-point dog ON
Md.29 Current feed value
Md.30 Machine feed value
Inconsistent
0
In error
Address at stop
Standing by
Inconsistent
In zero point return
Value the machine moved is stored
Fig. 8.3 Operation performed when the zero point is not passed in the near-point dog method
(5) If the restart command is turned ON after machine zero point return is stopped
upon a stop signal, an error “zero point return restart not possible” (error code:
209) occurs.