AnsweredAssumed Answered

Building Linked and Custom Graphic Displays

Question asked by sarslan Employee on Oct 25, 2017

Hi Guys,


Greg Martin had a good question: is the video and shows how to put color to an individual tag (based on temperature value) but nothing on how to do it in comparing two tags and showing a red dot when the value of the difference is out by X amt or x%.


So when two tag values are out by more than 5% or 10,000 I want a dot beside the values to turn red. There are many tags I want to compare and easier to highlight the ones in red that need to be looked at instead of manually reviewing all the numbers.


And Joey answered the question:

Thanks for the clarification. If you want to compare two tag values, my suggestion would be to set up a simple 'formula' attribute or 'Expression analysis' in AF to compute the difference (or % difference) and store the calculation history to a 'PI point data reference' attribute. You can then use the same logic explained in this video to configure a multi-state symbol using this analysis output attribute.

You can see the steps to configure expression analysis in this video:
Creating Calculations Using Expressions


She is correct in that this is the simplest way to set this up. Anytime you want to multistate a value, generally you should have a PI tag. You can then do the calculating in either PI AF analysis or in Processbook, under the PI calc. If you need anymore clarifiaction, please feel free to reach out to me in this thread or at


Greg, does this answer your question?