User`s manual

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3.3 Operation Processing
3.3.1 Initial processing
3
SEQUENCE PROGRAM EXECUTION
3.3 Operation Processing
This section explains the operation processing of the CPU module.
3.3.1 Initial processing
Initial processing is a preprocessing for execution of the sequence program operation.
When the PLC is power-on or the CPU module reset is canceled, the following processing
is executed only once.
• System setting
• Boot from the standard ROM*
• Safety CPU operation mode setting
• Self-diagnostics
• CC-Link Safety data setting
• Start of the MELSECNET/H network information setting and network communication
• CPU operation status determination
When the initial processing is completed, the CPU module is placed in the operation status
set by the RUN/STOP/RESET switch. ( Section 3.4)
*: In SAFETY MODE, booting is executed from the standard ROM regardless of the PLC
parameter boot file settings.
In TEST MODE, booting is executed from the standard ROM if booting from the
standard ROM is set at the PLC parameter boot file setting.
POINT
1. The CPU module’s RUN/STOP/RESET switche is shown in the figure below.
2. When a parameter or program has been changed in the STOP status, reset
the CPU with the RUN/STOP/RESET switch.
3.3.2 CC-Link Safety, MELSECNET/H refresh
Refresh is executed in the refresh range set with CC-Link and MELSECNET in the
network parameters.
CC-Link Safety and MELSECNET/H refresh is executed before the start of sequence
program operations.
When constant scan is executed, CC-Link Safety and MELSECNET/H refresh is executed
at each constant scan time.
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PULL
RESET
STOP
RUN
RUN/STOP/RESET switch