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Question: Remote UI Navigation Bug
My understanding of how the Vision on a Remote UI session navigates is by receiving callbacks from its associated _Ui_X DPEs. For example doing this dpSet() would cause the module (ModuleName) to display the provided panel (FileName):
dpSet(dp + "RootPanelOrigOn.ModuleName:_original.._value", ModuleName,
dp + "RootPanelOrigOn.FileName:_original.._value", FileName,
dp + "RootPanelOrigOn.PanelName:_original.._value", PanelName,
dp + "RootPanelOrigOn.Parameter:_original.._value", Parameters);
We have noticed that sometimes after a brief network interruption between the Remote UI and its Servers the vision continues to run but can not navigate away from the panels it currently has loaded in its modules.
I believe that this could be due to the reconnection not reestablishing the dpConnects on the _Ui_X DPEs. Is this a known issue with 3.18 P024 and if so which patch / version fixed it?
Is there any way of determining if the Remote UI has still got a connection open to the _Ui_X DPEs so we can potentially check and restart the vision automatically when this issue does occur?
We are using WinCC OA v3.18 Patch 24 on RHEL 8.8
Responses (3)
The connection to the event manager can be checked with the function isEvConnOpen: https://www.winccoa.com/documentation/WinCCOA/latest/en_US/ControlE_R/isEvConnOpen.html
Guess there are no standard control functions to check which hotlink connections are still open (like the report flag HOTLINKLIST provides).
Is it possible for a Remote UI to still be running without a connection to the Event Manager? I was of the understanding that Remote UIs need a permanent connection to the Event Manager otherwise you get the connection lost message popup and after a timeout the Remote UI terminates.
What we have observed is the connection lost popup briefly appearing (at which point more that likely the isEvConnOpen() function would return FALSE) but once the popup disappears the Remote UI modules are visible but can't load new panels into them. The panels that are loaded are still getting dpConnect callbacks as the displays are updating but the callbacks on the internal _Ui_X DP are not triggering callbacks or the callbacks are failing on the workstation side and not loading the panels into the requested module.
No all Manger have a connection to the Event Manger (unless you start some with -n)