8-1SectionCustomizable Counter Unit Operation
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8-1 Customizable Counter Unit Operation
This section explains the internal processing of the Customizable Counter Unit
8-1-1 Operation Flowchart
The overall flow of Customizable Counter Unit operation is as shown in the fol-
lowing flowchart.
Power application
Initialization of I/O, Work, AR, other
memory areas, timers (preset) and
CPU Unit communications.
Check hardware and
Program Memory.
Check OK?
No
Yes
Set error flags and
activate indicators.
ERROR or ALARM?
ALARM
(flashing)
ERROR
(lit)
Execute user’s program.
End of program?
Check cycle time setting.
Minimum
cycle time?
Wait until minimum cycle
time expires.
Compute cycle time and preset
cycle monitoring time.
Refresh contact I/O, special I/O,
and then CPU Unit communica-
tions.
Peripheral servicing
Initialization
Overseeing
processes
Program
execution
Cycle time
processing
I/O refresh
in Unit
Peripheral
servicing
Cycle time
No
Yes
No
Yes
Note The cycle time and scan time are the same.