OPC client does not take the Server-time on second start!

[michel.eijgermans]

In our 3.14 P07 Were using a OPC-DA-client connected to a local OPC-DA server. We want to use the Timestamp of a value that is available in the OPC-server. The OPC tag is not changed during the whole procedure described below.

With a running OPC-DA-client we configure an OPC address on a (new) datapoint-element. It then correctly receives the value and Timestamp of the OPC-server. After a restart op the WinCCOA-OPC-client the Timestamp is overwritten by the local-time of the machine.

The same behaviour occurs if you configure a (new) datapoint-element with a Simulation-driver running. The timestamp is zero and will be filled with the correct value and timestamp of the OPC-Server. After a restart the OPC-DA-client Timestamp is overwritten by the local-time of the machine.

The side-effect of this behaviour is that the datapoint element value is set to 'Invalid'. Probably this is due to the fact that the OPC-Client driver receives a Timestamp of the OPC-server that's older then the current Timestamp in the Datapoint element.

Am i facing a Bug? of do a miss a config-setting for OPC?

We have set a config-setting to use the Timestamp of the OPC-client-driver which resolves the Invalid state of the Datapoint-Element, but that's not the behaviour that we want. We want to use the Server Timestamp.

[alug]

I cannot reproduce this behaviour with our OPC Server. I get correct timestamps in all cases.
Can it be that the OPC server sends a "uncertain" value during driver restart?
You can try to activate -dbg 2 Debugoption during clients start. Than you should see what the client receives from the server.