Mitsubishi Electric Q26UD(E)HCPU User Manual page 258

(2) Replacement procedure of the Q6BAT battery for the High Performance model
QCPU, Process CPU, Redundant CPU and Universal model QCPU
Replacing battery
Backup the program and the
data.
Turn off the programmable controller
power supply.
Remove the CPU module from the
base unit.
Open the CPU module bottom cover.
Remove the old battery from its
holder.
Insert a new battery into the holder
in the correct direction. Connect the
lead to the connector.
Close the CPU module bottom cover.
Install the CPU module into the
base unit.
Turn on the programmable controller
power supply.
SM51 to verify
Monitor
SD52 to check if bit 0 is
Failure of CPU module battery
256
Monitor
OFF
on/off.
ON
Bit 0 is OFF.
ON.
Bit 0 is on.
Backup time
3 minutes
Connector CPU
module side
Connector
battery side
CPU module
Completed
Battery Q6BAT