The mapping between human readable properties and OPC paths

Ignition
,
1

In the designer tag browser, there's a mapping between human readable properties/tags and OPC item paths. Is that mapping generated at runtime or stored in the database somewhere? Is there some way to access it via scripting?

2

?

Please elaborate. OPC Item Paths only exist for OPC tags, and only contribute to any OPC tag's value, quality, and timestamp properties. And not separately.

There's no such thing as an OPC Item Path to any other tag properties.

If you mean Tag Paths, then the basic set of property keys can be retrieved from WellKnownTagProps. There are additional such collections for specific types of tags, modules can supply more, and anyone can create arbitrary custom property names.

You might wish to examine the code in my Tag Report Utility project in the Ignition Exchange if you wish to see how to obtain those properties, live, for a specific gateway's installed modules, and corresponding information for remote tag providers.

3

Thanks!

WellKnownTagProps is the sort of thing I'm looking for, just for tags that haven't yet been imported into the Ignition system as tags. (i.e. that exist only on the OPC server my gateway is connecting to)

4

You will want to examine the various system.opc.browse*() functions. The only thing that connects an OPC tag to its source are the OPC Server and OPC Item Path properties of the Ignition tag. All other tag properties are independently configured in Ignition only.

5

Yeah, I'm looking for a way, given an OPC server, to get every valid OPC item path. This might be something outside Ignition though

6

That's what those browse functions do. To the extent supported by the specific OPC server. (Servers and drivers can support item paths that aren't browseable, particularly when specific protocols lack any mechanism for enumeration. Lots of those.)