Compare Strings in Advanced Tag

[LS_10366301]

I'm trying to use a Derived tag to compare a string tag to some static strings and return boolean response for if it matches or not.  I was hoping the logic operator == would do this like it does for numerical values but expression validation returns "String tag expected".  Is there another logic operator to use to compare string values or do I have to do something different?

Using KepServerEX 6.14

Thanks!

[VladimirN]

Article - "Derived tags not allowing Arithmetic Function with String Tag in a single Expression in PTC Kepware Products": https://www.ptc.com/en/support/article/CS388921

[aservetas · Accepted solution]

It actually does work for String comparison. Please see the example below:

Then writing the same value to String2 evaluates correctly:

Best regards,

Andy Servetas
Principal Technical Support Engineer | Kepware Technologies

[LS_10366301]

Thanks to both of you for the responses!

With this information, I was able to confirm that my string comparisons only work when they are the only thing in the derived tag.  Since I had 4 strings to compare, it took me 5 tags instead of one to achieve my goal but it will work for now.  Would be nice to see PTC take this up as an enhancement, where I can do a string evaluation with == in a derived tag and then perform arithmetic functions on the result.