iFix 4.5, Equations in a TagGroup?

All,

We recently changed out a PCV from a direct acting to a reverse acting valve. Unfortunately the way the PLC code is written, it references everything as 0% being Fully Closed and 100% being fully open, and since the SCADA looks at that tag, it displays the inverse and is confusing to operators.

Also unfortunately, since everything is validated and standardized, it would be easier to find a quick solution SCADA side, which I think I did: I just updated the tag references(PCV_OUTPUT.F_CV) to (100 - PCV_OUTPUT.F_CV) and the valve animation works fine.

However, we have a control module pop-up where the user can see and enter a fixed output %. This screen uses a tag-group value that I changed also to 100 - PCV_OUTPUT.F_CV, and OnChange passes the new value on to the variable where the visible % output is stored.

With the 100 - PCV_OUTPUT.F_CV, the variable referencing the tag-group field does not seem to register when the tag changes, and only displays the correct value if you close and open the screen again. The OnChange in the VBA is not triggering.

Do TagGroup files not like to use equations, or is there a way around this?

Thanks.

I think I have done what you are asking, but not in a OnChange in VBA. The fact that code works in a Tag Group definition is very nice.

I would suggest reverting to your original code can then throwing PCV_OUTPUT.F_CV into a calc block and the result of that to the real world output. Or can you specify the scaling of the output block to be 100 to 0 vs 0 to 100 ? I think you *can* do that, might work. At least it did in DMACS. I don't have the iFix hard drive handy right now to try it out.