Omron CJ - 08-2008 - Computing the Cycle Time; CPU Unit Operation Flowchart

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Computing the Cycle Time Section 10-4
10-4 Computing the Cycle Time
10-4-1 CPU Unit Operation Flowchart
The CJ-series CPU Units process data in repeating cycles from the oversee-
ing processing up to peripheral servicing as shown in the following diagrams.
Normal Processing Mode
NO
YES
YES
NO
Sets error flags
I/O refreshing
ERR/ALM indicator
ON or Flashing?
ON (fatal error)
Flashing (non-
fatal error)
Executes user pro-
gram (i.e., executes
READY cyclic tasks).
End of program?
Resets watchdog
timer and waits un-
til the set cycle time
has elapsed
Calculates cycle
time
Performs I/O
refreshing
Services Program-
ming Devices
Check OK?
Checks hardware
and user program
memory
Checks Unit
connection status.
Power ON
Startup initializa-
tion
Overseeing pro-
cessing
Program execu-
tion
Cycle time cal-
culation
Peripheral servic-
ing
PLC cycle
time