Omron CJ2 CPU UNIT SOFTWARE User Manual page 311

Additional Information
Battery-free Operation
• Operating without a Battery
The following data can be held when the PLC operates without a battery.
• User program and network symbols
• Parameters (e.g., PLC Setup, registered I/O tables, routing tables, CPU Bus Unit settings,
PLC names)
• Data saved in the non-volatile memory in the CPU Bus Units and Special I/O Units
(e.g., protocol macro data in Serial Communications Units)
The following data is not held. The values will not be stable.
• I/O memory (including the Holding, DM, EM, and Auxiliary Areas)
• The clock built into the CPU Unit
• Setting Operation without a Battery
• PLC Setup
Set the PLC Setup as described below.
(1) The I/O memory will be unstable when there is no battery, so clear the IOM Hold Bit
Check Box so that the IOM Hold Bit is cleared at startup.
(2) Forced status will be unstable when there is no battery, so clear the Forced Status Hold
Bit Check Box so that Forced Status Hold Bit is cleared at startup.
(3) Select the Do not detect Low Battery Check Box.
• Programming
The operation of the Output OFF Bit will be unstable when there is no battery, so insert the
following instructions so that the Output OFF Bit does not turn ON.
LD P_Off
OUT A500.15
• Precautions for Operation without a Battery
Be careful of the following points when you operate without a battery.
• Initializing Data
Values in the DM Area, EM Area, and other I/O memory areas will be unstable. Be sure to
set the initial values from the program.
Example:
LD A200.11
MOV #0918 D0 // Initialization of D0 values at start of operation
• Unstable Clock
The clock built into the CPU Unit will not operate and the values will be unstable. Therefore, the
data on dates and times recorded in the error log will not be displayed correctly. Also, if files are
saved on a Memory Card, the date and time that the file was created will not be stable.
CJ2 CPU Unit Software User's Manual
9 PLC Setup
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