Appendix 3.2 Periodic Execution Block Replacement Method - Mitsubishi MELSEC-Q Series Programming Manual

APPENDICES

APPENDIX 3.2 Periodic Execution Block Replacement Method

(1) Operation of periodic execution block
A periodic execution block is executed in each scan where the specified execution interval has
elapsed.
The following figure shows the operation performed when blocks 0, 1, 2, 10 and 11 are used
and blocks 10 and 11 are set as the periodic execution blocks.
1 scan
Blocks
0, 1, 2
executed
Execution interval
(2) Periodic execution block replacement method
When the execution interval measured by the timer in the sequence program reaches the set
time, the specified block is activated by the STOP/RESTART bit.
When the set time is not reached, the block is in a stop status.
To hold the output also when the block is in a stop status, select "Change OUT instruction in
specified block to SET instruction" or "Coil output held for stop-time output mode".
SM402
SM400
Tn
APP -21
1 scan
Blocks Blocks
0, 1, 2 10, 11
executed executed
Execution interval
SET BLm
Set interval
Tn
Corresponding block
STOP/ RESTART bit
RST Tn
1 scan
Blocks Blocks
0, 1, 2 0, 1, 2
executed executed
1 scan
Blocks
10, 11
executed
APP -21