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6.2.5
Fixed scan execution type program
(1) Fixed scan execution type program
(a) Fixed scan execution type program is an interrupt program executed at
specified time intervals.
Interrupts in units of files are available without interrupt pointers or the IRET
instruction.
(2) Execution of fixed scan execution type program
(a) When two or more fixed scan execution type programs exist, a fixed scan
execution type program which reaches the specified time is executed.
When two or more fixed scan execution type programs reach the specified
time at the same timing, the programs are executed in ascending order of
the numbers in the program setting of the PLC parameter.
(b) When a fixed scan execution type program and an interrupt program (I28 to
I31) reach the specified time at the same timing, the interrupt program is
executed first.
(c) When the execution condition is established during the network refresh, the
network refresh is interrupted and an interrupt program is executed.
Therefore, note that even though the "Block data assurance per station"
setting is set in the CC-Link IE or MELSECNET/H network, this setting is
invalid when a device set as a refresh target is used in the fixed scan
execution type program.
10ms
10ms
10ms
10ms
Interrupt factor
Fixed scan execution
type program execution
Link refresh execution
The link refresh is suspended and the fixed
scan execution type program is executed.
(d) Execution during END processing
When the execution condition is established during the constant scan
execution or the waiting time of the END instruction, a fixed scan execution
type program is executed.
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