Dear Mr. Luth,

I'm writing you as contact person in charge of the Unified Architecture Working Group, from which I would need a clarification on OPC UA specifications.

I have a scenario with a single OPC UA Server not in redundant configuration, which is exposing ServiceLevel = 0.

In this scenario, the OPC UA Client is not able to establish a connection to the server because it detects ServiceLevel = 0 and assumes the server is in maintenance mode.

My understanding is that the client in this case is adhering to the correct behavior expected by the OPC UA Standard, as described here. The server, even when in standalone mode and not in redundant configuration, should always properly set the ServiceLevel according to the specification:

All Servers, regardless of Redundant Server Set membership, shall adhere to the sub-ranges defined in Table 109.

Is my interpretation correct, or should the Client check and take in account ServiceLevel information only when connecting to a redundant server set?

I hope you or someone in the Working Group can help me clarify this doubt.

Thank you very much in advance and best regards,

Benedetto Bozano

Siemens Digital Industries Software

DI SW MOM PPM MES