I am trying to create a UDT to show input status of a digital input card. I want to show not only the state of the digital input but also the description of the tag.
Here is a screenshot of one of the inputs.
I can easily access the .Data part of the tag.
Is there a way to get the description as well?
I know with HMI's you can create a parameter file and use .Data@Description to get the description. Anyway to do the same for Ignition?
This is proprietary for FactoryTalk HMI or whatever you're referring do.
Rockwell does not document how 3rd parties might access these attributes. They don't seem to be available via standard CIP attributes.
I haven't had a chance to RE those.
That would be a game changer if your driver supported them. While I'm assuming those are read only, it would provide a way to have consistent documentation between the PLC and HMI.
I haven't pushed hard because there's no easy way to expose them in the UA model. "Description" is an attribute already given over to browse text. It would have to be its own UA Node.
I will second it would be awesome to have live.
We use that field for our ParseL5K tool for bulk imports to Ignition, but that is offline stuff.
It would be nice in general to map the OPC UA "Description" attribute to Ignition's "Documentation" property on OPC tags...
The problem is the only time I actually have this attribute value is when you are browsing and doing a drag n' drop operation to create an OPC tag.
I don't have a reasonable answer for keeping them up to date or even reading the Description when a tag is created any other way.
Ergo my separate node thought. Suffix to an Item Path that triggers driver-specific interrogation of the PLC. Presuming the RE succeeds. 
Yes, that's definitely the right approach for now.
I think in the future I should just get around to implementing generic system.opcua.read and system.opcua.write scripting functions that let you read/write any OPC UA attribute.
With those in place, if you want to map attributes to tag props, it's possible and you can figure out how/when to sync however works best for your project.
Now that I've conquered the Device interface, this makes a great deal of sense. 
Agreed. The closest I’ve come to reading ‘live’ values of extended properties is via use of Logix SDK. Latest library permits uploading an entire project via Python, then saving as L5X, and parsing accordingly (newer firmwares only).
Ability to read extended props via opc.readValue would be handy!
FYI the latest FactoryTalk Linx Gateway v6.5 allows reading meta data using the @ symbol from within Ignition.
Not something I love to use but it is available for Ignition users now. I'm guessing Wireshark wouldn't show anything useful to see how they do it.
Ive setup UDT"s to read in DI and DO
I tried setting up a string tag with the following path and still no luck.
Was this what you meant?
Seems a little over my head...but if I understand correctly once you have the OPC UA server set up with the plc you can create a script and use system.opcua.read function to read in the description?
This was all theoretical discussion. The @Description attribute and others like it are not available to us.
