UI dpConnect to distributed systems

[ewoenne]

Hi,

I have a UI which has several dpConnects to shows dps from different distributed systems. The UI behaves differently depending on when it is started:

- if I start the UI when the local project is completely running but a dist system is not, once the dist system is connected then the UI recovers and shows the datapoints correctly

- however, I have a UI which runs automatically on startup so I suspect the UI starts before all managers have started. Sometimes this UI never recovers and shows certain distributed dps as disconnected, even after the systems are connected. Restarting the UI fixes the problem

Are there certain managers which need to be running in a project for the UI dpConnects to a distributed system to recover automatically?

[leoknipp]

The difference might be if the system has already loaded the identification for the distributed system or not.
If the identification is already loaded and the system is not connected at the moment the dpConnect() knows the DP element for the distributed system and will therefore not fail. When the dpConnect() was possible (did not return an error) the dpConnect() will refresh automatically if the distributed system is connected. In case of wantsAnswer = 1 when calling the dpConnect() you will get a hotlink when the connection is established.

When the identification is not loaded the dpConnect() will fail with an error "DP does not exist".
In that case the automatic refresh will not work.

Can you please check which errors you get in the cases you have described.

Best Regards
Leopold Knipp
Senior Support Specialist

[ewoenne]

Thank you for the explanation Leopold, the "DP does not exist" error is the difference between the two cases.

So the automatic refresh will only work if the dist system has previously been connected (and the UI started after this identification is loaded)?

[leoknipp]

Yes, the automatic refresh will only work if the DP element is known when the dpConnect() is made.

Best Regards
Leopold Knipp
Senior Support Specialist