Tag failing for OPC-UA complex data type

When I add a tag from an OPC-UA server that has a custom Data Type, the tag has a red exclamation mark and does not read correctly.

Below is a screenshot of accessing the tag in UA Expert (double-click to read the values):

Below is an excerpt of the log during the add tag process:

Were there any warnings from DataTypeDictionaryReader when the connection was established?

If not, can you turn that logger to DEBUG and then edit/save connection and upload the logs?

Doesn’t appear so…

I’ve attached a log with all OPC log items set to Trace. I restarted the gateway and edited the OPC connection, then added the offending tag “Present Test Value”.
Ignition-ap2l1tst-000mod_Ignition_logs_20200505-1044.idb (240 KB)

It doesn’t look like this server is exposing a DataTypeDictionary defining the custom types.

If you browse to the DataType Node in UaExpert (Types > DataTypes > BaseDataType > Structure > TestValueType probably), does it have a DataTypeDefinition attribute? If so, this is probably why UaExpert can read the value but Ignition can’t - this is new in OPC UA 1.04.

Ignition can only read custom datatypes if they’re defined in a DataTypeDictionary as specified in OPC UA versions prior to 1.04.

Yes, that appears to be the case. Thanks for the pointer.


Obligatory question: is moving to OPC-UA 1.04 in the works?

Yes, but not at in any timeframe that’s going to help you now. It would be a feat if it even happened this year.

Contact the vendor of the server and ask if there’s a way to enable the DataTypeDictionary for custom types.

Hi @Kevin.Herron

Anyway, this is not so simple. Most new versions of companion specifications are based on OPC UA 1.04. This is the case from VDMA companion specifications. Most of these companion specifications are using structured data types (OPC UA structures). More recent OPC UA servers support 1.04. So i would suggest to increase the priority of Structured data types support.

Best regards

Hi @Kevin.Herron

I wish you a very happy new year.

Any news on the subject of custom data types support based on OPC UA 1.04?

No it’s still a distant prospect. The stack is still 1.03 and work on implementing 1.04 has no starting timeframe right now.