Mitsubishi Electric Q26UD(E)HCPU User Manual page 606

● Use the battery within the time shown by the guaranteed value of the battery life.
● If the battery may be used exceeding the time shown by the guaranteed battery life value, perform the following.
• Perform boot operation to protect a program even if the battery dies at the programmable controller power-off.
• Back up programs and data after SM52 turned on (within the backup power time after an alarm).
● When the battery (Q6BAT) is not connected to the CPU module, its service life is five years.
● When the battery-low special relay SM52 turns on, immediately change the battery.
Even if an alarm has not yet occurred, it is recommended to replace the battery periodically according to the operating
condition.
● The battery (Q7BAT and Q8BAT) is not available for the Basic model QCPU.
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