Some buffer memory values are cleared when the power is turned off. Turn on the backup command before turning the power OFF.
By turning the buffer memory Un\G399, b8 (setting value backup command) OFF to ON, the target data is written to the non-volatile memory of the FX5-4LC.
After buffer memory Un\G360, b13 (set value backup flag) is OFF, turn Un\G399, b8 (setting value backup command) OFF.
For the buffer memory to be backed up, refer to the following manual.
MELSEC iQ-F FX5 User's Manual (Temperature Control)