OPC UA data type "Variant"

General Questions
1

Hi all,

currently I am trying to connect a Stäubli CS9 emulator to VC using OPC UA.
Connection works fine and I can browse the server structure.
On server side, the type of the joint angles is specified as “Variant” and the variables can not be paired with VC variables.

grafik
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In the OPC UA reference, Variant is specified as a union of all other data types.
https://reference.opcfoundation.org/v104/Core/docs/Part6/5.1.6/
Is this type not implemented in the OPC UA client of VC? Or is there any other way to read this type?

Thanks for your support.

2

There is no support for variants, only a specific set of data types which are listed in the VC help file.

Generally the server data type must be known and remain static so such “runtime defined” data types are not supported by any of the VC Connection plugins.

This seems quite strange / lazy way to model the OPC UA server structure anyway and I can guess that not many OPC UA clients can read such values.

btw. VC Premium has the Stäubli add-on that can connect to CS9 emulator and do time-synchronized co-simulation with it.

3

Ok thanks for your response.

You’re right, I wasn’t able to read that type with the TwinCat OPC UA client either. I will wait what the Stäubli support recommends me to do.

Yeah I read that before, but it will be a hard task to convince my company to upgrade our licences. Looks like I need to find a workaround, something using TwinCat, for the near future :slight_smile: