Mitsubishi Electric MELCEC Q Series User Manual page 114

7. MEMORY CARD AND BATTERY
The life of the Q6BAT is approximately 10 years when it is not installed in a CPU module or
when it is installed in a CPU module with the power always on. The Q6BAT should be
immediately replaced when it has been used exceeding the time shown by the guaranteed
value and M9006 turns on.
Even when the Q6BAT has been used less time than the guaranteed value of the table
above, it is recommended to replace the battery in the following years to ensure preventive
maintenance.
1) Ten years for Q02CPU-A
2) Four to five years for Q02HCPU-A and Q06HCPU-A
Replace the battery for the SRAM card immediately after M9048 turns on.
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