I have a UDT that I am using across the plant. That UDT has an tag within it with a "Sensor Fault" alarm for when the signal goes below 4mA. This is a UDT I am using several hundred times over with all of the expressions set in the UDT itself, not per tag.
The problem is, I have an expression to set the Display Path of the Sensor Fault alarm. That expression should show the tag name along with a typical "Sensor fault" messaging. That Tag name is determined via another tag in the UDT ("_DispName"). On SOME of these devices that display name comes across as "Null" when the alarm activates. I have ensured that the DispName tag is filled correctly, but for whatever reason on a handful of these it doesn't come across.
Attached are the photos. There is the expression tag that shows what is being put into the display, the output of one that is not working, and the _DispName tag that should fill in. Can anyone see what is happening?
