Selection Transition - Mitsubishi Electric MELSEC-Q Series Programming Manual

Selection transition

A "selection transition" is the transition format in which several steps are coupled in a parallel manner, with processing
occurring only at the step where the transition condition is satisfied first.
Item SFC diagram
Branch
Coupling
Up to 32 steps can be available for selection in the selection transition format.
When two or more selection step transition conditions are satisfied simultaneously, the left-most condition will take
precedence.
4 SFC PROGRAM CONFIGURATION
60
4.3 Transition
Description
• From step "n", processing will proceed to either step "n+1" or step
"n+2", depending on which transition condition ("b" or "c") is satisfied
first.
• If both transition conditions are satisfied simultaneously, the
condition to the left will take precedence. Step "n" will then be
deactivated.
• Subsequent processing will proceed from step to step in the selected
column until another parallel coupling selection occurs.
When the transition condition ("b" or "c") at the executed branch is
satisfied, the executed step ([A] or [B]) will be deactivated, and
processing will proceed to step "n+2".
If transition conditions "c" and "d" are satisfied simultaneously, the step "n+2"
operation output will be executed.