MITSUBISHI ELECTRIC Mitsubishi Programmable Logic Controller QD75D - Manual (Page 480)

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MELSEC-Q
12 CONTROL SUB FUNCTIONS
12.2 Sub functions specifically for machine OPR
The sub functions specifically for machine OPR include the "OPR retry function" and
"OP shift function". Each function is executed by parameter setting.
12.2.1 OPR retry function
When the workpiece goes past the OP without stopping during positioning control, it
may not move back in the direction of the OP although a machine OPR is commanded,
depending on the workpiece position. This normally means the workpiece has to be
moved to a position before the near-point dog by a JOG operation, etc., to start the
machine OPR again. However, by using the OPR retry function, a machine OPR can
be carried out regardless of the workpiece position.
The details shown below explain about the "OPR retry function".
[1] Control details
[2] Precautions during control
[3] Setting the OPR retry function
[1] Control details
The following drawing shows the operation of the OPR retry function.
(1) OPR retry point return retry operation when the workpiece is within the range
between the upper and lower limits.
1) The movement starts in the " Pr.44 OPR direction" by a machine OPR start.
2) The operation decelerates when the limit signal OFF is detected.
3) After stopping at detection of the limit signal OFF, the operation moves at the " Pr.46 OPR speed" in the
direction opposite to the " Pr.44 OPR direction".
4) The operation decelerates when the near-point dog turns OFF.
5) After stopping due to the near-point dog OFF, a machine OPR is carried out in the " Pr.44 OPR
direction".
6) Machine OPR completion
5) 1)
Near-point dog
Limit signal OFF ON
2)
3) 6)
4)
Zero signal
Fig. 12.1 OPR retry operation by limit signal detection