Identifier of Datatypes|OPC UA Standard|Forum|OPC Foundation

Hello Andre,

Nodes are collected into a “namespace”, which is an organization of these nodes. You can have multiple namespaces within the global address space. The official OPC UA data-types exist in namespace 0, so a UA-native String data-type should look like this:

ns=0;i=12

That is the official STRING data-type NodeId.

The other NodeId you mention refers to a completely different type altogether. But, since you didn’t mention the namespace part of the NodeId I can’t help but wonder if it is in a different namespace. Why would it be in a different namespace? because it could be a custom-type defined by Siemens. That’s the one purpose of a namespace, to organize nodes/types from a different standard.

Here is a link to all of the namespace=0 nodes (official UA types): https://github.com/OPCFoundati…..odeIds.csv

I hope this helps.

Like any other types, OPC UA allows to create sub-types. So if this Server has a very specific string (e.g. a string that contains a hex format) this can be expressed in the type system. Clients – when they find a data type they don’t know – can always browse the type hierarchy until they find a super-type they know. But Clients that do know this Server and its custom types will know the specifics for this string.

That said, the type on the wire and provided in a Read response will still be a string.