Mitsubishi Q Series Programming Guide

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6 SFC PROGRAM EXECUTION
MELSEC-Q
6.1.1 SFC program resumptive START procedure
The SFC program START format can be designated as “initial START” or “resumptive START”.
The “resumptive START” setting procedure as well as some precautions regarding the
“resumptive START” format are described below.
(1) Resumptive START setting procedure
Make the resume START setting of the SFC program in the "SFC program start mode" of the
SFC setting in the PLC parameter dialog box.
(2) Block operation status resulting from “SFC program START mode” setting
At an SFC program start, whether an initial start or resume start will be made is determined by
the combination of the setting of the "SFC program start mode" in the PLC parameter dialog
box and the ON/OFF status of the "special relay for setting SFC program start status (SM322)".
Initial Start Resume Start
SFC Program Start Mode
Operation
SM322: OFF
(Initial status)
1
SM322: ON
(When changed
by user)
SM322: ON
(Initial status)
1
SM322: OFF
(When changed
by user)
SM321 is turned from OFF ON Resume Initial
PLC power is switched OFF, then ON Resume/Initial 3 Initial
PLC power is switched OFF, then ON after
SM321 ON
OFF or RUN STOP
Resume 2 Resume 2
Reset operation to RUN Initial Initial
Reset operation to RUN after SM321 ON
OFF or RUN STOP
Initial Initial
Resume
2 Resume 2
STOP RUN Resume
STOP program write RUN Initial Initial/Resume 4
Initial: Initial start, Resume: Resume start
1: SM322 is turned ON/OFF by the system according to the setting of the "SFC program start
mode" in the PLC parameter dialog box when the CPU module switches from STOP
RUN.
• At initial start setting: OFF
• At resume start setting: ON
2: Operation at resume start
At a resume start, the SFC program stop position is held but the status of each device used
for the operation output is not held.
• Therefore, make latch setting for the devices whose statuses must be held in making a
resume start.
The held coil HOLD step SC becomes inactive, and is not kept held.
In the Basic model QCPU, the held coil HOLD step SC restarts in the held status.
However, the output is not held. To hold the output, make latch setting for the devices
desired to be held.
3: Depending on the timing, a resume start is disabled and an initial start may be made. When it
is desired to make a resume start securely, turn SM321 from ON
OFF or switch the CPU
module from RUN
STOP, and then power the PLC OFF, then ON.
Note that the Basic model QCPU and Universal model QCPU always makes an initial start.
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Mitsubishi Q Series Specifications

General

Brand	Mitsubishi
Model	Q Series
Category	Control Unit
Language	English