Look up 'retentive ranges'. Unlike the Allen-Bradley processors, the AD processors would happily zero out everything on startup unless told otherwise. That's where 'retentive ranges' comes in. It just tells the processor what NOT to zero out. There are some ranges already included. Check to see if the registers you want are included. If not modify the ranges. Be careful though. Make sure you aren't assuming that some items start with zero. If included in the 'retentive range' it could be anything.