Battery Replacement - Mitsubishi Electric MELSEC iQ-F FX6U Hardware User Manual

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 is turned on. However, the drop in battery
voltage may not be detected immediately. Prepare a new battery and replace the battery with the 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
7
6
5
4
3
2
1
0
Replacement procedure
If the battery voltage is reduced, replace it following the procedure below.
Even with the battery removed, the built-in capacitor holds the data of the memory for the power interruption time (20 sec.).
Battery replacement steps 3 and 4 must be completed within 20 seconds. If the time taken for battery replacement is longer
than the power interruption time, the data of the memory may be lost.
1.
Turn the power supply off.
2.
Remove the expansion board connector cover (A in figure below). If an expansion board is installed, remove it.
8 MAINTENANCE AND INSPECTION
170
8.3 Battery
0 10 20 30 40
Ambient temperature [Degrees]
A
5
2
50