Expression Tag inside a UDT

Ignition
1

Hello,

I want to add an Expression Tag inside a UDT but the expression I want to write is based in the AlertCurrentSeverity meta property of another OPC Tag inside the same UDT.

It’s something like this:

//UDT:
Pump {
   floatOPCtag      Temp;  //This has analog alerting
   floatOPCtag      Level;  //This also has analog Alerting
   intExpressionTag Status;
}

//Expression for Status:
if(Temp.AlertCurrentSeverity>Level.AlertCurrentSeverity,
   Temp.AlertCurrentSeverity,
   Level.AlertCurrentSeverity)

Colby gave me some hints using templates here
viewtopic.php?f=71&t=8032
but I can’t get it done using only UDTs

Is there a way to do this?

2

That’s considerably easier than the last problem. Here’s the expression you want:

if({[.]Temp.AlertCurrentSeverity}>{[.]Level.AlertCurrentSeverity}, {[.]Temp.AlertCurrentSeverity}, {[.]Level.AlertCurrentSeverity})

Basically, in any expression anywhere, you can refer to a tag through “{tagpath}”. A tag path can be relative or absolute, and the example above simply has the relative root source definition, “[.]”, required for referencing things inside of the UDT (the relative “[~]” would also work).

Anyhow, once you can reference a tag, you can reference a property of that tag through “.prop”.

Regards,

3

Ahhhhh That is great!

I always get surprised of the simplicity of your answers!

Thanks a lot!!