Operation Without A Battery - Omron NX-PA Series User Manual

6 Inspection and Maintenance
Precautions for Safe Use
• Before you replace the Battery, you must first supply power to the Controller for at least 5
minutes, and then you must complete this procedure within 5 minutes at 25°C after turning
OFF the power to the CPU Unit to ensure memory backup. If power is not supplied for at
least 5 minutes, the saved data may be lost.
• Never short-circuit the battery terminals; never charge the battery; never disassemble the
battery; and never heat or incinerate the battery. Doing any of these may cause the battery to
leak, heat, ignite, or rupture.
• Never use a battery that has been dropped on the floor or otherwise subject to shock. It may
leak.
• Turn ON the power after replacing the Battery for a CPU Unit that has been unused for a long
time. Leaving the CPU Unit unused again without turning ON the power even once after the
battery is replaced may result in a shorter battery life.
Additional Information
The Low Battery Voltage event is cleared automatically the next time the Controller is turned
ON after replacing the Battery.
6-2-2

Operation without a Battery

The NX-series CPU Units do not support a battery-free operation function such as CJ-series CPU
Units. If a Battery is not connected or the Battery voltage is too low, the following operation occurs.
• A Low Battery Voltage, Battery-backup Memory Check Error, and Real-Time Clock Stopped events
are detected.
• The _RetainFail (Power Retention Failure Flag) system-defined variable will be TRUE.
 Retaining or Not Retaining Data in the CPU Unit
Data in the CPU Unit will be retained or not retained as described in the following table according to
whether there is a Battery.
User program
Controller Configurations and Setup
Event log
Clock data
Values of variables
*1. If the initial value setting is blank, the initial value for the data type is used. For example, the initial value of
BOOL data is FALSE and the initial value of integer data is 0. Refer to the NJ/NX-series CPU Unit Software
User's Manual (Cat. No. W501) for details on the initial values.
6 - 10
Type of data
No Retain attribute
Retain attribute
Power turned ON
Battery
Values before power interruption will be retained by the
built-in non-volatile memory.
Values before power inter-
ruption will be retained.
Correct values
*1
Initial values
Values before power inter-
ruption will be retained.
NX-series CPU Unit Hardware User's Manual (W535)
No Battery
Values before power inter-
ruption will not be retained.
Illegal values
*1
Initial values
*1
Initial values