Mitsubishi Electric MELSEC-L LD75D, User Manual

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CHAPTER 12 CONTROL SUB FUNCTIONS
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(c) Setting the dwell time during an OPR retry
The OPR retry function can perform such function as the dwell time using "[Pr.57] Dwell time at OPR retry"
when the reverse run operation is carried out due to detection by the limit signal for upper/lower limits and
when the machine OPR is executed after the near point dog is turned OFF to stop the operation.
"[Pr.57] Dwell time during OPR" is validated when the operation stops at the "A" and "B" positions in the
following drawing. (The dwell time is the same value at both positions "A" and "B".)
(2) Control precautions
• The following table shows whether the OPR retry function may be executed by the "[Pr.43] OPR method".
*1 Starting can be executed from the position of the limit switch installed in the opposition direction of "[Pr.44] OPR
direction". (The limit signal is OFF.) Note that the retry operation with the limit switch placed in the OPR direction cannot
be executed because the stopper is installed in the OPR direction.
• Always establish upper/lower limit switches at the upper/lower limit positions of the machine, and connect
them to the LD75. If the OPR retry function is used without hardware stroke limit switches, the motor will
continue rotation until a hardware stroke limit signal is detected.
• Do not configure a system so that the drive unit power turns OFF by the upper/lower limit switches
connected to the LD75. If the drive unit power is turned OFF, the OPR retry cannot be carried out.
[Pr.43] OPR method Execution status of OPR retry function
Near-point dog method  : Execution possible
Stopper method 1)
 : Execution possible
*1
Stopper method 2)
 : Execution possible
*1
Stopper method 3)  : Execution not possible
Count method 1)

: Execution possible
Count method 2)

: Execution possible
Machine OPR
executed again
Stop by near-point
dog OFF
Stop by limit
signal detection
Reverse run operation
after limit signal detection
B
OP
Pr. 44 OPR direction
Machine OPR start
A
Limit signal OFF
Near-point dog
Zero signal