Mitsubishi Electric MELSEC iQ-R Series User Manual page 599

A warning or error does not occur even if the processing time is exceeded.
Check the processing time on the execution time monitor.
In some cases, the operation load of fixed scan operation type programs can cause an operation cycle over to
occur.
■Standby execution type
The program is executed at execution request.
The program is converted to a normal execution type program and then executed by using a PSCAN instruction from another
running program.
Flow of program execution
The flow of execution for each program is shown below.
■Processing for initial execution type programs when PLC READY [Y0] is ON
The timing chart for processing that is executed when PLC READY [Y0] is ON is shown below.
Processing for initial execution type programs is interrupted by operation cycle processing.
Priority
High
Operation cycle processing
Initialization processing at RUN
Initial execution type program 1
Initial execution type program 2
Low
When the PLC READY [Y0] is turned from OFF to ON
Fixed scan type programs are not executed until the processing for initial execution type programs completes,
even if an EI instruction is issued during an initial execution type program.
Operation cycle processing execution cycle
Time
APPX
Appendix 2 Motion Module Programs
A
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