Problems with the OPC Connector for older OPC DA servers?

[Former Member]

Hello,

we are developing a solution involving OPC data access and want to utilize xMII as a gateway between the OPC server and our application. The xMII installation we use works fine with three different demoservers we connected, even when accessing them remotely.

When first trying to connect to our real datasource, we encountered problems. The namespace was not browsable from within the xMII Query Template editor. A taglist was given though, but the tags did not give proper results. The general log stated, that an "invalid server" was being used.

Other OPC clients which are designed for diagnostic use did not have any problems with namespace browsing or accessing the data in our server, so the problem was limited to the use of xMII. Reconfiguring the namespace of the OPC server led to data access working in xMII, but the namespace is still not browsable from within xMII.

We use a Simatic NET OPC Server, which states it fulfills OPC DA specification 1.0A and SAP xMII 11.5.1 with an OPCDatasource2_5_0_4beta Connector. The question is, if our problems could arise from our use of such an old OPC specification in the server? It is stated that the DataSource Connector works with "any OPC server", but as I understand it the actual specification is OPC DA 3.0, which would be quite a distance in versions.

Thanks in advance for any useful hints!

Andreas Gössling

[Former Member · Accepted solution]

Andreas,

The OPC UDS (version 2.5.0.4) is capable of reading the OPC DA 2.05A Specification only. Unfortunately if the OPC DA Server you are trying to connect to doesn't support this specification, then the UDS will not work properly.

Martin

[Former Member · Accepted solution]

Hello Martin,

thanks a lot for the answer! This is exactly the information I need to explain my senior staff members why it is not my fault.

Luckily, I found a stable state for cooperation between my components. Now I have the validation that this state must not be altered by others.

Thanks again!

Andreas