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

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.
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.
Periodic execution block operation method
Periodic execution block operation occurs as shown below.
• Until the specified time interval elapses, only the sequence programs and blocks designated for execution at each scan will
be executed.
• 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.
• The specified time interval countdown is executed in a continuous manner.
• 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.
• To execute the periodic execution block, the block to be executed periodically must be activated.
• The fixed-cycle execution block setting is not available for the Basic model QCPU, Universal model QCPU,
and LCPU.
4 SFC PROGRAM CONFIGURATION
4.7 SFC Operation Mode Setting
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