Omron NSJ CONTROLLERS - 03-2008 Operation Manual page 152

Power OFF Operation
1,2,3...
Note
Power OFF detection
voltage
Power OFF
detected signal
Program execution
status
CPU reset signal
1. Insert DI(693) before the program section to be protected to disable inter-
rupts and then place EI(694) after the section to enable interrupts.
2. Set the Disable Setting for Power OFF Interrupts in A530 to A5A5 Hex to
enable disabling power interruption processing.
Note A530 is normally cleared when power is turned OFF. To prevent this,
the IOM Hold Bit (A50012) must be turned ON and the PLC Setup
must be set to maintain the setting of the IOM Hold Bit at Startup, or
the following type of instruction must be included at the beginning of
the program to set A530 to A5A5 Hex.
A20011
First Cycle Flag
3. Disable the Power OFF Interrupt Task in the PLC Setup.
With the above procedure, all instructions between DI(693) and EI(694) (or
END) will be completed (see note 1) before the Power OFF Interrupt is exe-
cuted even if the power interruption occurs while executing the instructions
between DI(693) and EI(694).
1. The protected instructions can be completed only when the time required
to complete execution is less than or equal to the processing time after
power interruption detection (2 ms). If the instructions are not completed
within this time, they will be interrupted and the Controller Section will be
reset.
2. The processing time after a power interruption is detected is 1 ms when a
CJ1W-PD022 is mounted. The Controller Section will thus be reset 1 ms
after the power interruption occurs.
3. If the Power OFF Interrupt Task is not disabled in the PLC Setup, the Power
OFF Interrupt Task will be executed, and the Controller Section will be re-
set without executing the protected instructions as soon as the power in-
terruption is detected.
4. If a power interrupt is detected while DI(693) is being executed, the Con-
troller Section will be reset without executing the protected instructions.
When Power OFF Interrupt Task Is Disabled and A530 = A5A5 hex
(to enable disabling power interruption processing)
Power OFF detected
Power OFF
detection time:
NSJ Controller: 2 ms
AC: 10 to 25 ms
PD025: 2 to 5 ms
PD022: 2 to 10 ms
Cyclic tasks
If A530 is not set to A5A5 hex, operation will be as normal, i.e., execution of
the current instruction will be completed and then power interrupt processing
will be performed.
Set A530 to A5A5 Hex at the
MOV beginning of the program to enable
#A5A5
disabling power interruption
A530
processing.
Operation always stopped
at this point regardless.
Holding time for 5 V internal power
supply after power OFF detection
Power OFF confirmed
Power OFF Detection
Delay Time: 0 ms
Instructions between
DI(693) and EI(694)
are executed.
Section 7-1
Processing time after
power OFF is confirmed:
2 ms PD022: 1 ms
Note: The interrupt task
execution time must be
less than or equal to the
processing time after
power OFF is confirmed.
Stopped
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