12 - 4
MELSEC-Q
12 CONTROL SUB FUNCTIONS
12.2 Sub functions specifically for machine OPR
The sub functions specifically for machi ne OPR include the "OPR retry function" a nd
"OP shift function". Each function is execut ed by parameter setting.
12.2.1 OPR retry function
When the workpiece goes past the OP without stop ping during positioning control, it
may not move back in the direction of the OP a lthough a machine OPR is commanded,
depending on the workpiece position. This n ormally 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 retr y function, a machine OPR can
be carried out regardless of the workpiece pos ition.
The details shown below explain about the "OP R 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 th e OPR retry function.
(1) OPR retry point return retry operation when t he 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