User`s manual

Battery life and replacement procedure Maintenance and inspection
MELSEC System Q, Hardware 10 – 19
% Install the CPU module into the base unit.
& Turn on the programmable controller power supply.
' Monitor SM51 to verify on/off.
If the special relay is still set, indicating with SD52 a low CPU battery voltage, retry the
replacement. Check the battery voltage. If it is too low for the memory card, the battery must
be replaced (refer to next section 10.3.3).