Periodic Execution Block Setting - Mitsubishi MELSEC-Q Series Programming Manual

4 SFC PROGRAM CONFIGURATION

4.7.4 Periodic execution block setting

The periodic execution block setting designates the execution of a given block at specified time
intervals rather than at each scan.
(1) Setting items
Designate the first block number and the time of execution for the periodic execution blocks.
When these settings are designated, the "first block" and all subsequent blocks will become
periodic execution blocks.
The execution time interval setting can be designated in 1 ms units within a 1 to 65535 ms
range.
(2) Periodic execution block operation method
Periodic execution block operation occurs as shown below.
(1)
1 scan
Execution interval
1) Until the specified time interval elapses, only the sequence programs and blocks designated
for execution at each scan will be executed.
2) When the specified time interval elapses, the periodic execution blocks will be executed
following execution of blocks designated for execution at each scan. If the specified time
interval is shorter than the scan time, the periodic execution blocks will be executed at each
scan in the same manner as the other blocks.
3) The specified time interval countdown is executed in a continuous manner.
POINT
(1) When the parameter where the "High speed interrupt I49 fixed scan interval" has been set
is written to the High Performance model QCPU whose first five digits of serial No. are
"04012" or later, the fixed-cycle execution block setting cannot be used.
If the fixed-cycle execution block setting is made, no processing is performed and the block
remains unchanged from the every scan execution block.
(2) To execute the periodic execution block, the block to be executed periodically must be
activated.
(3) The fixed-cycle execution block setting is not available for the Basic model QCPU,
Universal model QCPU, and LCPU.
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(2) (3) (1) (2)
1 scan
(4) (3) (1) (2)
1 scan
Execution interval
(1) Sequence programs executed at each scan
(2) Blocks executed at each scan
(3) END processing
(4) Periodic execution blocks
(3) (1) (2) (4)
1 scan
(3)
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