Mitsubishi Electric MELSEC-L02SCPU User Manual page 115

(4) Near-point dog and starting position of machine OPR
If machine OPR is performed at a position where the near-point dog is turned on, the following operations take
place under each OPR method:
• Near-point dog method: Machine OPR starts at the creep speed.
• Count 1 or count 2: Machine OPR is performed according to the OPR retry function.
Ex.
Count 1
OPR direction
Decelerates and stops
by near-point watchdog
OFF.
Near-point watchdog
(5) Precautions
• If a limit signal is not selected by the built-in I/O function setting, the OPR retry function does not operate and
the mechanical system may also be damaged as the axis continues to operate to the limit of the machine
system.
• If the near-point dog method is used, make sure the area in which the limit switch turns off does not overlap
with the area in which the near-point dog turns on. An attempt to start machine OPR in an overlapped area
generates "Retry error" (Axis 1 error code: 1202) and the axis stops. If the two areas are overlapped during
OPR retry, "Retry error" (Axis 1 error code: 1202) may occur regardless of the OPR method (near-point dog
method, Count 1 or Count 2) and the axis may stop.
• Make sure the limit signal in the direction opposite the OPR direction does not turn off during machine OPR.
A "Hardware stroke limit +" error (Axis 1 error code: 1100) or "Hardware stroke limit -" error (Axis 1 error
code: 1101) occurs and the axis stops.
• Do not start machine OPR in an area where the limit signal in the direction opposite the OPR direction is off.
A "Hardware stroke limit +" error (Axis 1 error code: 1100) or "Hardware stroke limit -" error (Axis 1 error
code: 1101) occurs and machine OPR does not start.
Decelerates by near-point watchdog ON.
Movement amount after
near-point watchdog ON
Start point
With near-point
watchdog ON
ON
CHAPTER 7 POSITIONING FUNCTION
Origin
Zero signal
OFF
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