Omron Sysmac CPM1 Operation Manual page 11

Application Precautions
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If the power remains off for a period exceeding the data backup period,
AR 1314 will turn ON to indicate that the capacitor can no longer back up data
and the data backed up by the capacitor will be cleared. AR 1314 will remain
ON unless it is turned OFF using I/O monitor operations, using memory clear
operations, or from the user program.
If desired, the PC Setup setting in DM 6604 can be set to create a fatal error
and thus stop the system when AR 1314 goes ON.
• The data stored in flash memory will not be lost even if power remains off for a
period exceeding the data backup period, because the data stored in flash
memory will be read to the CPU Unit when the CPM1 is turned on.
• If the power is turned off without changing the mode from PROGRAM mode to
RUN or MONITOR mode after having made changes in the data that is backed
up in flash memory, the changes will not be written to flash memory. If the
power is then left off for more than 20 days (at 25_C), the changes (i.e., the
contents of the RAM) will be erased and the data values will become unde-
fined.
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