Battery Replacement - Mitsubishi MELSEC iQ-F series User Manual

Setting an optional battery using the engineering tool
The following setting is required when the capacity of the latch device/latch label is increased using the optional battery.
Note that the battery does not back up the data if the following setting is not provided.
Select the Navigation window[Parameter][FX5UCPU][CPU Parameter][Memory/Device Setting][Device/Label
Memory Area Setting][Option Battery Setting][Mounted]

Battery replacement

Battery life and replacement guidelines
When the battery voltage is low, the BAT LED on the panel flashes red while the power is on, and SM51 (SM8005) and SM52
(SM8006) turn ON. The memory can be retained for about one month after the LED turned on. However, the drop in battery
voltage may not be detected immediately. Prepare a new battery and replace the battery with new one promptly.
Standard life of FX3U-32BL: 5 years (at ambient temperature of 25)
The life of the battery changes with respect to ambient temperature.
When planning for battery replacement, please estimate the battery life according to the graph below and
order replacement batteries in advance.
Battery life vs. temperature
8 MAINTENANCE AND INSPECTION
124
8.3 Battery
7
6
5
4
3
2
1
0
0 10 20 30 40
Ambient temperature [Degrees]
50