Block Execution Sequence - Mitsubishi Electric MELSEC-Q Series Programming Manual

Block execution sequence

In the SFC program, the step in the active block is executed every scan. When there are multiple blocks, the blocks are
processed in order of lower to higher block numbers.
• In the active block, the active step in that block is executed.
• The inactive block is checked for a START request, and if there is a START request, the block is activated and the step in
that block is executed.
The SFC program is executed in order of  to .
: Whether block 0 is active or inactive is checked.
: Since block 0 is active, the active step (S2) is executed.
: Whether block 1 is active or inactive is checked.
: Since block 1 is active, the active step (S0) is executed.
: Whether block 2 is active or inactive is checked.
: Since block 2 is inactive, whether the next block is active or inactive is checked.
5 SFC PROGRAM PROCESSING SEQUENCE
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5.3 SFC Program Processing Sequence