Mitsubishi Electric MELSEC iQ-R Series Programming Manual page 114

Simultaneous sequence (divergence/convergence)
All the steps branched from one step are activated simultaneously. When all the steps immediately before convergence are
activated and the common transition becomes TRUE, the active state transitions to the next step.
Item Description
Divergence
(1)
(3)
(7)
Convergence
(1)
(5)
(8)
• The simultaneous sequence allows transitions to up to 32 steps.
• If another block is started by the simultaneous sequence, the START source block and START destination block will be
executed simultaneously.
• A simultaneous convergence is always performed after a simultaneous branch.
■ Precautions
• When the steps connected by a convergence include HOLD steps [SC, SE, ST] that hold operations, the operation is
performed as follows.
Item
Coil HOLD step [SC]
Operation HOLD step (without transition
check) [SE]
Operation HOLD step (with transition
check) [ST]
• In the simultaneous convergence, a block start step (with END check) [BC] cannot be created immediately before the
convergence. Use a block start step (without END check) [BS].
8 SFC PROGRAM
112
8.2 Structure
(2)
(4)
(5) (6)
(8)
(2)
(3) (4)
(6)
(7)
Description
A transition to the next step does not occur the same as an inactive step.
A transitions to the next step occurs if another connected step is active.
When the transition (2) becomes TRUE while the step (1) is active, both of the step (3)
and step (4) are activated at the same time.
The step (1) becomes inactive. However, if it is a HOLD step [SC, SE, ST], the step
holds the coil output or action according to its attribute.
Processing will proceed to step (7) when transition (5) becomes TRUE, and to step (8)
when transition (6) becomes TRUE.
When the transition (3) and transition (4) become TRUE while the step (1) and step (2)
are active, the step (5) and step (6) are activated.
After the step (5) and step (6) immediately before the convergence become active, the
transition (7) is checked and then becomes TRUE, the step (8) is activated.
The step (5) and step (6) become inactive. However, if it is a HOLD step [SC, SE, ST],
the step holds the coil output or action according to its attribute.