Operation When Battery Is Exhausted Or Not Installed; Continuing Operation; Saving Data - Omron CJ2 CPU UNIT User Manual

7 Inspection and Maintenance
7-2-2

Operation When Battery Is Exhausted or Not Installed

The CJ-series PLCs can operate even when the Battery is exhausted or not installed.

Continuing Operation

To have operation continue when the Battery is exhausted or not installed, set the parameter in the PLC
Setup so that Battery errors are not detected.

Saving Data

The user program and parameter area data are saved in flash memory even when the Battery is
exhausted or not installed. I/O memory (such as the CIO Area), however, cannot be saved.
Conditions for Operation
Operation is possible when the Battery is exhausted or not installed if the following two conditions both
apply.
• There is no need to save data in I/O memory.
• There is no need to use initial settings in the DM/EM Area, or the initial settings are made by the user
program.
Additional Information
You can use the function for automatic transfer from the Memory Card at startup to store data in
I/O memory and the DM/EM Area even when the Battery is exhausted or not installed.
The following table shows when the Battery is required according to the purpose of CPU Unit operation.
Saving I/O memory is required.
Saving to I/O
memory is not
required.
Restrictions
• The clock function cannot be used, so the values for the Calendar/Clock Area (A351 to A354) and the
Startup Time (A510 to A511) in the Auxiliary Area will be unstable. In addition, the times at which the
CPU Unit created files on the Memory Card will be unstable.
• The Total Power ON Time (A523), Power Interruption Time (A512 to A513), and Number of Power
Interruptions (A514) in the Auxiliary Area will all be all zeros at startup.
• Error log data will not be held in the Error Log Area (A100 to A199) in the Auxiliary Area at startup.
• Correct values may not be held in I/O memory (including the HR, DM, and EM Areas) at startup. In
the PLC Setup, set the IOM Hold Bit (A500.12) and the Forced Status Hold Bit (A500.13) to not be
held at startup.
7-8
DM/EM Area initial values are
DM/EM Area ini-
set from the Memory Card.
tial values are
required at star-
DM/EM Area initial values are
tup.
set from the user program.
DM/EM Area initial values are not required at star-
tup.
The Battery is required.
Automatic transfer from the Mem-
ory Card at startup is set. (Pin 2 is
set to ON.)
Normal operation from flash
memory or operation using the
Memory Card is possible.
CJ2 CPU Unit Hardware User's Manual