Behavior When An Active Step Is Activated - Mitsubishi Electric MELSEC iQ-R Series Programming Manual

Behavior when an active step is activated

When an active step is activated, the step behaves as follows.
Series sequence
(1)
(2)
Selective sequence
■ Divergence
Transitions are checked from left to right. If the step connected to the transition having a TRUE value is active, the steps
behave in the same way as in the series sequence. After the first TRUE path is taken, transitions are no longer checked.
■ Convergence
The steps behave in the same way as in the series sequence.
(1)
Simultaneous sequence
■ Divergence
If any one of the steps in divergence of the simultaneous sequence is active, all steps below the transition become active in
the next scan.
(1)
(3)
(2)
■ Convergence
All steps above the transition become inactive. The HOLD steps [SC, SE, ST] hold operations.
When the transition (2) becomes TRUE, the step (1) becomes inactive.
(2)
(4)
When the transition (2) becomes TRUE, the step (1) becomes
inactive.
When the transition (1) becomes
TRUE, the steps (2) to (5) become
active in the next scan.
(5)
8.7 SFC Program Execution
8 SFC PROGRAM
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