D0 to D511 do not hold by default, and D511 holds by default. So when programming, pay attention to the allocation of data addresses. If you need to keep the power off, try to choose the D area after D511.
Before D511, it needs to be set to the power-off hold range, after D511, it is not necessary to set the power-off hold
my fx3u-32mt device doesn’t save the value when the power goes out. i tried D600~D5000. is there any way to help me. battery 3v ok.