Chapter 6 Sfc Program Execution; Sfc Program Start And Stop - Mitsubishi Electric MELSEC-Q Series Programming Manual

6
SFC PROGRAM EXECUTION
This chapter describes the SFC program execution.
6.1

SFC Program START and STOP

There are the following four types of SFC program start and stop methods.
• Auto START using PLC parameter
• Start and stop using the special relay for SFC program start/stop (SM321)
• Start and stop using the PSCAN/POFF instruction (except the Basic model QCPU)
• Start and stop using the programming tool (except the Basic model QCPU, Universal model QCPU, and LCPU)
Auto START using PLC parameter
Set "Start Conditions" in the "SFC" of the PLC parameter dialog box to "Autostart Block 0". The SFC program is started when
the CPU module switches from STOP to RUN. (When the SFC program starts, block 0 also starts.)
Start and stop using the special relay for SFC program start/stop (SM321)
SM321 turns ON when an Auto START is made using the PLC parameter.
• Turn OFF SM321 to stop the SFC program execution.
• Turn ON SM321 to start the SFC program.
Start and stop using the PSCAN/POFF instruction (except the Basic model QCPU)
• When the POFF instruction is executed, the SFC program in execution turns off the output and then stops. The execution
type changes to the "stand-by type".
• When the PSCAN instruction is executed, the stand-by type SFC program can be started. However, when the SFC
program has not been set to the "scan execution type" (SM321 is OFF) in the program setting of the PLC parameter dialog
box, the SFC program is started by turning ON Sm321. The execution type changes to the "scan execution type".
6 SFC PROGRAM EXECUTION
158
6.1 SFC Program START and STOP