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8 ZERO POINT RETURN CONTROL
8.2.4 Zero point return method (2): Stopper stop method 1)
The machine starts a machine zero point return.
(The machine starts acceleration specified in " Pr.53 Zero point return acceleration time selection" in the
1)
direction set in " Pr.46 Zero point return direction", and moves at " Pr.48 Zero point return speed".)
The machine detects near-point dog ON and starts deceleration.
2)
(At this time, torque limit is required. If torque limit is not applied, the servomotor may fail at 4).)
The machine decelerates to " Pr.49 Creep speed" and then moves at the creep speed.
3)
4)
The machine comes into contact with the stopper at the creep speed, and stops.
When " Pr.51 Zero point return dwell time" has elapsed after near-point dog ON, pulse output from the
5)
D75P2 stops and "deviation counter clear output" is output to the drive unit.
After the completion of "deviation counter clear output", the zero point return complete flag (RX(n+2)0,
6)
RX(n+5)0) turns from OFF
ON
OFF.
Machine zero point return start
(Positioning start signal)
Zero point return request flag
[RX(n+1)F, RX(n+4)F]
Zero point return complete flag
[RX(n+2)0, RX(n+5)0]
Deviation counter clear output
Axis operation status
[RWrn+7, RWrn+1.5]
Md.44 Movement amount
after near-point dog ON
Current feed value
[RWrn+0 to 1, RWrn+8 to 9]
Md.30 Machine feed value
The following shows an operation outline of the "stopper stop method 1)" zero point
return method.
Operation chart
ON and the zero point return request flag (RX(n+1)F, RX(n+4)F) turns from
V
1)
Near-point dog OFF
ON
OFF
ON
OFF
OFF
Standing by
In zero point return
Inconsistent
0
Inconsistent
Value the machine moved is stored
Fig. 8.3 Stopper stop method 1) machine zero point return
Pr. 48 Zero point return speed
2)
3)
Valid torque limit range
Torque limit
ON
Dwell time measurement
8 - 8
Pr. 49 Creep speed
Stopper
t
4)
5) 6)
Range in which the servomotor rotation
is forcibly stopped by the stopper
Time out of dwell time
ON
Standing by
Zero point address
MELSEC-A
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