Hello,
when starting a process on a remote-machine (e.g. a web-client-UI) two connections are opened:
UI-manager data-manager
UI-manager event-managher
The connection to the data-manager is only used during the UI-intialization or when requesting historical data. The answer on a historical data request is sent directly from the data-manager to the UI-manager.
The connection to the event-manager is used for transferring actual/current data to the UI-manager, e.g. when switching a panel, answers on dpGet-calls, current values for the work-function of a dpConnect ....
When using a normal remote-UI also alive-messages are transferred in a given interval, if the alive-mechanism is not deactivated using the config-entries aliveInterval and/or alivePort.
A webclient-UI is not sending alive-messages.
In case of a webclient-UI the connection user-interface data-manager is inactive most of the time.
In some cases inactive connections are closed by the network/firewall or some other parts in the network.
This might lead to an inconsistent manager connection state for the data- and event-manager because the event-manager has more UI-connections than the data-manager.
As an aftereffect you might see log-messages that connections (UI-manager data-manager) are broken/established several times without a restart of the user-interface.
Also it could lead to problems when starting a new UI without a defined UI-number. The UI-number is assigned by the data-manager. If the UI gets a number which is still in use by the event-manager the connection event-manager UI-manager cannot be established and you'll get a "this manager is already connected" log-message.
In this case please check your network to detect why inactive connections are closed and change the settings to avoid closing inactive connections.
How the configuration has to be changed has to be clarified with the system administration for the network and/or the installed computers.
Best Regards
Leopold Knipp
Senior Support Specialist
inactive (webclient-) connection is closed by the network/firewall
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