Download QCPU(Q Mode)/QnACPU Programming Manual (SFC)

4 SFC PROGRAM CONFIGURATION
MELSEC-QnA
POINTS
(1) The coil HOLD step becomes inactive the first time processing occurs at the block in
question following the STOP request.
(2) During SFC program execution, the M325 special relay is switched OFF when the coil
output is OFF, and is switched ON when the coil output is ON, in accordance with the
parameter setting.The M325 special relay can also be switched ON and OFF by the user
program without regard to the parameter setting.
3) The STOP/RESTART bit switches ON when the SFC control “block STOP” instruction
(PAUSE BLm) is executed.
(2) RSTART
1) The block in question is restarted from the step where a STOP occurred.
An “operation HOLD status” step (with transition check or without transition check) which
has been stopped will be restarted with the operation HOLD status in effect.
A “coil output HOLD” step cannot be restarted after being stopped as it becomes
deactivated at that time.
2) Execution of PLS and P instructions after a block STOP has been canceled varies
according to the ON (HOLD) or OFF (all OFF) status of the SM325 special relay (ON:
operation output HOLD at block STOP; OFF: all OFF).
SM325
ON: Not executed
OFF: Executed again
3) If the block restart instruction (RSTART BLm) is executed while the block is stopped, the
block STOP/RESTART bit switches OFF.
[Operation Error]
• Error No. 4621 occurs when the specified block does not exist or when the SFC program is
in the standby status.
[Program Examples]
(1) Block 1 is stopped when X1 switches ON, and is restarted when X2 switches ON.
X1
PAUSE
BL1
X2
RSTART BL1
Related Instructions
1) SFC information register
• Block STOP/RESTART bit.............................................See Section 4.5.3.
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