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Details

Type: Bug
Resolution: Fixed
Priority: P2: Important
Fix Version/s: 5.15.2, 5.15
Affects Version/s: 5.15.0
Component/s: OpcUA
Labels:
None

Platform/s:

Windows

Description

Develop OPC UA Client with QML. Test with UA Demo server.

After first endpoint discovery, QtOpcUa.Connection.connectToEndpoint works fine, ValueNodes are updating.

But after disconnectFromEndpoint, and connectToEndpoint again, connection status is connected, but ValueNodes are not updating anymore.

See the example code. After first start everything fine: status connected and value is updating. After click Disconnect button and Connect again - ValueNode doesn't update value from server anymore.

import QtQuick 2.12
import QtQuick.Window 2.12
import QtQuick.Controls 2.3
import QtOpcUa 5.15 as QtOpcUa

Window {
    visible: true
    width: 640
    height: 480
    title: qsTr("Hello World")

    QtOpcUa.Connection {
        id: connection
        backend: "open62541"
        defaultConnection: true
    }

    QtOpcUa.ServerDiscovery {
        id: serverDiscovery
        discoveryUrl: "opc.tcp://127.0.0.1:48020"
        onServersChanged: {
            if (!count)
                return;
            endpointDiscovery.serverUrl = at(0).discoveryUrls[0];
        }
    }

    QtOpcUa.EndpointDiscovery {
        id: endpointDiscovery
        onEndpointsChanged: {
            if (!count)
               return;
            connection.connectToEndpoint(at(0));
        }
    }

    QtOpcUa.ValueNode {
        nodeId: QtOpcUa.NodeId {
            identifier: "s=Demo.Dynamic.Scalar.String"
            ns: "4"
        }
        id: demoString
    }

    Button {
        x: 14
        y: 13
        width: 112
        height: 40
        text: connection.connected ? "Disconnect" : "Connect"
        visible: true
        onClicked: {
            if (connection.connected)
                connection.disconnectFromEndpoint()
            else
                connection.connectToEndpoint(endpointDiscovery.at(0));
        }
    }

    Text {
        x: 14
        y: 68
        width: 346
        height: 28
        text: demoString.value
    }
}