Is there a way to expose the .@ description from a tag in studio 5000 to an ignition HMI without adding a string to my UDT and copying my descriptions over?
No, not with our driver or any other driver I'm aware of. Somebody recently mentioned that FactoryTalk supports it. Whatever the mechanism is, Rockwell does not document it.
The @ descriptions and other metadata are only available in newer Rockwell software, I have never seen a third party platform that supports them at all.
If any driver can do that it would be FactoryTalk Linx Gateway. That functionality falls into the realm of Rockwell “secret sauce” which is undocumented features that Rockwell uses internally but doesn’t expose to other vendors presumably to give themselves a competitive advantage.
I don’t have a test environment set up currently to confirm this but I think linx gateway has an option to expose these properties. It’s an extra activation cost so it might not make sense to go this route unless it really impacts what you’re trying to do. You will see a tag read performance improvement with linx Gateway with large tag loads also because it uses secret sauce to read values faster than their official, documented OPC interface can.
It’s always easier to use the Ignition driver so we only use the Linx Gateway one when we have a special situation.
We use the normal Ignition driver for normal size projects and Linx Gateway for projects with larger tag loads coming from Rockwell PLCs. We also use it on pre-version 20 PLCs that are likely to be upgrade to 20+ firmware because the tagpath doesn’t change in linx gateway when the PLC upgrades so the PLC upgrade is a little smoother down the road.
I don’t know if everyone has this option but we can request a temporary activation from our Rockwell vendor to test things out so you don’t have to buy an activation to see if it works for you.
Anyway, I’m just throwing this out there in case it is helpful for you.