Non-volatile memory GX Works2

[williamj]

Hi all, Im trying to figure out how to create non-volatile memory tags in GX Works 2 (using a FX3U controller), so that the values stored in the D registers won't keep zeroing out every time the controller powers down. Does anyone have any helpful tips on how this is done? Thanks

[JRoss]

You need to add a battery to the PLC. You have limited control over which data registers are retentive by setting parameters, but the battery is needed for any of them to retain their values.

[Crossbow]

RTFM. There is a list in the manual (Chapter 4 I believe, where it identifies each of the memory areas) and it clearly lists which addresses are battery backed and which are not. In the FX3U, besides a range of D registers you also have all of the R registers which are all backed up.