Mitsubishi Melsec-Q Series User Manual page 283

11.3.3 Replacement procedure of the CPU module battery
Replace the battery of the CPU module by the following procedures when it comes to the end of its life.
The programmable controller power must be on for 10 minutes or longer before dismounting the battery.
Data in the memory are backed up for a while by a capacitor even after the battery is removed. However, since data in
the memory may be erased if the time for replacement exceeds the backup time shown in Table11.9 to Table11.12,
replace the battery quickly.
(1) Replacement procedure for the Basic model QCPU's Q6BAT battery
Replacing battery
Backup the program and the
data.
Turn OFF the programmable controller
power supply.
Open the CPU module front 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 front cover.
Turn ON the programmable controller
power supply.
Monitor
SM51 to check
ON/OFF.
Monitor
SD52 to check if bit 0 is
ON.
Failure of CPU module battery
OFF
ON
Bit 0 is OFF.
Bit 0 is ON.
Figure 11.2 Replacement procedure for the Q6BAT battery
CHAPTER11 MAINTENANCE AND INSPECTION
Table11.9 Backup time
Backup time
3 minutes
Connector CPU
module side
Connector
battery side
Completed
11
CPU module
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