Omron CP1E CPU UNIT SOFTWARE User Manual page 281

Precautions for Safe Use
Power Interruptions during Backup
The BKUP indicator on the front of the CPU Unit will be lit when DM Area data is being saved to
the built-in EEPROM backup memory.
Do not turn OFF the power supply to the PLC while the indicator is lit. If the power supply to the
PLC is turned OFF while the BKUP indicator is lit, data will not be backed up. In this case, the
DM Backup Restore Failed Flag (A751.11) will turn ON when the power supply is turned ON
again. Therefore, the backup data will not be restored to the DM Area. Transfer the data from the
CX-Programmer to the DM Area again.
Precautions for Correct Use Precautions for Correct Use
• To prevent operation from starting if the DM backup data is not restored correctly when the
power supply is turned ON, insert the following instructions into the ladder program to gener-
ate a fatal error.
A751.11
DM Backup Restore Failed Flag
• To ensure concurrency between DM backup data and the contents of the DM Area in the
RAM, use exclusive processing in the ladder program so that contents of the DM Area words
in the RAM that are set to be backed up are not changed during a backup operation.
DM Backup Save Flag
A751.14
• Data can be written up to 100,000 times to the built-in EEPROM backup memory. Data cannot
be written once this limit is exceeded. If writing fails, A315.15 (Backup Memory Error Flag) will
turn ON.
Additional Information
Confirming Completion of DM Area Backup
If user programs or the parameter area is being saved to the backup memory using operations
from the CX-Programmer, the backup operation will not be executed immediately even if
A751.15 (DM Backup Save Start Bit) is turned ON. A751.14 (DM Backup Save Flag) will remain
ON during this time and turn OFF when the DM backup operation has been completed. You can
confirm the completion of DM backup by checking to see if the DM Backup Save Flag (A751.14)
has been turned OFF.
CP1E CPU Unit Software User's Manual(W480)
FALS
10
#0000
Programming to change the
contents of DM Area words
that are set to be backed up
16 Other Functions
Generates a user-defined
fatal error
DM Area words that are set to be backed up will
not be changed during a backup operation to
ensure concurrency between DM backup data
and words in the DM Area in the RAM.
16
16-11