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CHAPTER 2 APPLICATION OF PROGRAMMING
2
2.4 Scan Time Structure
2.4.1 Initial Processing
2.4 Scan Time Structure
A CPU module sequentially performs the following processing in the RUN status. Scan time is the time required for all
processing and executions to be performed.
2.4.1 Initial Processing
The CPU module performs pre-processing required for program operations. The processing is performed only once
when any of the operations described in the following table is performed. When initial processing is completed, the
CPU module will enter the status set using the RUN/STOP/RESET switch. ( Page 71, Section 2.5)
: Performed, × : Not performed
*1 The operation indicates that the status is changed back to RUN without resetting the module after any parameter or
program was changed in the STOP status. (The RUN/STOP/RESET switch is set from STOP to RUN (the RUN LED will
flash), then back to STOP and to RUN again.) Note that the PLS, P instruction (instruction for pulse conversion) may
not be executed properly with the above operation. This is because the previous information may not be inherited
depending on the program changes.
Initial processing item
CPU module status
Powered-on Reset
Changed from STOP to RUN
*1
The I/O module initialization ×
Boot from a memory card or SD memory card ×
PLC parameter check
Multiple CPU system parameter consistency check
Initialization of devices outside the latch range
(bit device: off, word device: 0)
×
Automatic I/O number assignment of mounted modules
CC-Link IE and MELSECNET/H information setting ×
Intelligent function module switch setting ×
CC-Link information setting ×
Ethernet information setting ×
Initial device value setting
Serial communication function setting ×
Power-on or reset
Scan time
( )
( )
( )
( )
Initial processing
Refresh processing
Program operation
END processing
Page 70, Section 2.4.4
Page 69, Section 2.4.3
Page 68, Section 2.4.2
Page 67, Section 2.4.1
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