Power Off Operation; Operating Mode At Startup; Run Mode Set As Startup Mode; Program Mode Set As Startup Mode - Omron NJ501-1 Series User Manual

Additional Information
The CPU Unit internally performs initialization when the power to the Controller is turned ON.
The following processing is performed for initialization.
Self diagnosis at startup
Data check
Detecting CJ-series Units
Recording Power Turned ON and
Power Interrupted events
* 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.

Operating Mode at Startup

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.

• RUN Mode Set as Startup Mode

Power
Operating mode
RUN indicator
RUN output on
Power Supply Unit
4-1-2

Power OFF Operation

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 conditions,
to monitor the power supply voltage of the external devices as required.
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.
NJ-series CPU Unit Hardware User's Manual (W500)
Process
CPU Unit Startup
Time at Power ON
Startup RUN mode
Flashing Lit
ON
WARNING
Description
Operation is monitored for the following errors: Power Supply
Error, CPU Unit Reset, CPU Unit Watchdog Timer Error, and
Incorrect Power Supply Unit Connected. *
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.
The CJ-series Units mounted in the Controller are detected.
The Power Turned ON and Power Interrupted events are
recorded.

• PROGRAM Mode Set as Startup Mode

Power
CPU Unit Startup
Time at Power ON
Operating mode Startup
RUN indicator Flashing
RUN output on
Power Supply Unit
4 Installation and Wiring
PROGRAM mode
OFF
OFF
4
4-3