Basically i have a Total Volume Tag I want to snapshot it into Current Month and Previous Month Calculation Tags on the 1st of the month at 8am.

Volume = 1000
Snap = 500
Cmonth = Volume - Snap

At the rollover time move the Cmonth to the Pmonth
and then move the Volume into the Snap.

Does anyone have any good ideas in how to do this in VTScada?

Thanks,

Use a trigger tag for this. You can choose the source and destination tags. If you want to do a handful of actions at the same time then you can have the trigger activate a multi-write tag.

You can also check out the statistics tags and use the same Trigger to write those calculations to an I/O & Calc tag at scheduled intervals where they will be, by default, stored in the historian.

Let me know if this answers your question or if you could use some additional support here.

Thanks Dave, that works simpler then trying to do it all in expressions.