Omron NJ501-1400 - Power off Operation

4-3
4 Installation and Wiring
NJ-series CPU Unit Hardware User’s Manual (W500)
4-1 Processing at Power ON and Power OFF
4
4-1-2 Power OFF Operation
Additional Information
The CPU Unit internally performs initialization when the power to the Controller is turned ON.
The following processing is performed for initialization.
*Refer to 5-1-2 Fatal Errors in the CPU Unit on page 5-3 for information on the following errors: Power Sup-
ply Error, CPU Unit Reset, CPU Unit Watchdog Timer Error, and Incorrect Power Supply Unit Connected.
The system will immediately enter RUN mode if RUN mode (default) is set as the startup operating
mode. The system will immediately enter PROGRAM mode if PROGRAM mode is set as the startup
operating mode.
Different operations will be performed when the power is turned OFF depending on whether the power
interruption time is longer than the power OFF detection time, as described below.
Process Description
Self diagnosis at startup Operation is monitored for the following errors: Power Supply
Error, CPU Unit Reset, CPU Unit Watchdog Timer Error, and
Incorrect Power Supply Unit Connected. *
Data check The _RetainFail (Retention Failure Flag) system-defined variable
changes to TRUE at the following time: when the values of vari-
ables for which the Retain attribute was set to retain the values
and the values in DM, EM, and HR Areas in the memory used for
CJ-series Units were not retained after a power interruption.
Detecting CJ-series Units The CJ-series Units mounted in the Controller are detected.
Recording Power Turned ON and
Power Interrupted events
The Power Turned ON and Power Interrupted events are
recorded.
Operating Mode at Startup
4-1-2 Power OFF Operation
WARNING
The NJ-series Controller continues normal operation for a specific period of time
even when a momentary power interruption occurs. The Controller may therefore
receive incorrect signals from external devices that are affected by the momentary
power interruption.
Take suitable actions, such as external fail-safe measures and interlock condi-
tions, to monitor the power supply voltage of the external devices as required.
• RUN Mode Set as Startup Mode • PROGRAM Mode Set as Startup Mode
CPU Unit Startup
Time at Power ON
CPU Unit Startup
Time at Power ON
Operating mode
Power
RUN output on
Power Supply Unit
RUN mode
ON
RUN indicator
Operating mode
Power
RUN output on
Power Supply Unit
RUN indicatorFlashing Lit
Startup PROGRAM mode
OFF
Flashing OFF
Startup