Namespaces

In OPC UA, a namespace is used to logically assign nodes and avoid naming conflicts between different information models or manufacturers. The unique identification is done via the NamespaceUri, not via the numerical NamespaceIndex.

The NamespaceIndex simply corresponds to the current position of a namespace in the server's NamespaceArray. As this assignment can change, clients should not accept a NamespaceIndex statically or save it permanently. Instead, the required index should be determined again from the NamespaceArray for each connection using the associated NamespaceUri.

The following table shows an example of the NamespaceArray in the TwinCAT OPC UA Server.

In the TwinCAT OPC UA Server it is not possible to change the order of the namespaces or to freely define the NamespaceIndex.