Mitsubishi Electric MELSEC-Q Series Programming Manual page 173

■Operation when the target block is attempted to be started while online change (inactive
block) is executed
The target block does not start. The following table shows operations depending on block start method.
Start method (activation method)
Block START step (without END check)
Block START step (with END check)
SFC control instruction (SET BL , SET S ,
SET BL\S  instructions)
SFC information device (block START/END bit)
In the STOP or PAUSE status, an active step holds the activated status. Therefore, when the CPU module is
set to STOP or PAUSE while the target block is active, online change (inactive block) cannot be executed to
the block.
Ex.
Program example to execute the Block START instruction during online change (inactive block)
Operation at block start
• The target block does not start until when online change (inactive block) is ended. Even when the
transition condition for the step is met, the processing does not move to the next step.
• The target block starts after online change (inactive block) is ended. When the transition condition is met,
the processing moves to the next step.
• The target block does not start until when online change (inactive block) is ended.
• The target block starts after online change (inactive block) is ended. When the transition condition for the
step is met, the processing moves to the next step.
The target block does not start. While an instruction contact remains on, the target block starts after online
change (inactive block) is ended (for a program to execute the Block START instruction, refer to the
following program example.
The target block does not start even when the block START/END bit turns on. When the block START/END
bit is on, the target block starts after online change (inactive block) is ended. (The status of the block
START/END bit does not change until when online change (inactive block) is ended).
6 SFC PROGRAM EXECUTION
6.6 Operation at Program Change
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