Omron SYSMAC CS Series Operation Manual page 530

Power OFF Operation
Power OFF Timing Chart
85% of rated
voltage
Power OFF
detected signal
Program execution
status
CPU reset signal
Description of Operation
1,2,3...
492
The following timing chart shows the CPU Unit power OFF operation in more
detail.
Power OFF detected
Power OFF Detection
Power OFF detec-
Delay Time: 0 to
tion time: Default is
10 ms (set in PLC Set-
10 to 25 ms (Pow-
up)
er OFF undeter-
mined)
Cyclic tasks or interrupt tasks
not associated with power OFF
Power OFF Detection Time
The time it takes to detect power OFF after the power supply falls below 85%
of the rated voltage.
Power OFF Detection Delay Time
The delay time after power OFF is detected until it is confirmed. This can be
set in the PLC Setup within a range from 0 to 10 ms. (The default is 0 ms.)
Power Holding Time
The amount of time (fixed at 10 ms) that 5 V will be held internally after power
shuts OFF. The time that it takes for the power OFF interrupt task to execute
must not exceed 10 ms minus the Power OFF Detection Delay Time (process-
ing time after power OFF is confirmed). The power OFF interrupt task will be
ended even if it has not been completely executed the moment this time
expires.
1. Power OFF will be detected if the 100 to 120 V AC, 200 to 240 V AC or 24 V
DC power supply falls below 85% of the rated voltage for the power OFF
detection time (somewhere between 10 to 25 ms).
2. If the Power OFF Detection Delay Time is set (0 to 10 ms) in the PLC Set-
up, then the following operations will be performed when the set time ex-
pires.
a) If the power OFF interrupt task is disabled (default PLC Setup setting)
The CPU reset signal will turn ON and the CPU will be reset immedi-
ately.
b) If the power OFF interrupt task is enabled (in the PLC Setup), the CPU
reset signal will turn ON and the CPU will be reset after the power OFF
interrupt task has been executed. Make sure that the power OFF inter-
rupt task will finish executing within 10 ms minus the Power OFF De-
tection Delay Time = processing time after power OFF. The 5-V
internal power supply will be maintained only for 10 ms after power
OFF is detected.
Operation always stopped
at this point regardless.
Holding time for 5 V internal
power supply after power
OFF detection: 10 ms.
Power OFF confirmed
Power OFF
interrupt task
Section 10-3
Processing time after
power OFF is confirmed:
10 ms minus Power OFF
Detection Delay Time
Note: The interrupt task
execution time must be
less than or equal to pro-
cessing time after power
OFF is confirmed.
Stopped