Calculated tags from OPC tags

I have a few OPC flow rate tags that I would like to add together to create a total flow rate tag. For example flow1+flow2+flow3=Total flow. I then want to log the calculated tag in the same table with the OPC tags. I’m wondering if Fsql can do this and what the syntax would look like.

Just put the 3 tags in a historical group and add an Action Item that adds them together.

Right-click or hit CTRL-Space in the action item expression box to bring in the other OPC items, it will look something like:


Yeah, what Carl said, plus I wanted to add: if you only want to store the calculated value and not all of the inputs, just make them “Read Only” (found on the item edit screen).