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Trying to read OPC UA value with Delphi

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support
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30 Aug 2017 14:40 #5464 by support

Replied by support on topic Trying to read OPC UA value with Delphi

Does your code work with some other server? For example, our public demo server (the one used in examples?) It can easily be that the Node ID is correct, but the server is rejecting it for a reason that is outside of our control.

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eh
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30 Aug 2017 13:49 #5463 by eh

Replied by eh on topic Trying to read OPC UA value with Delphi

I still get the same exception... BadNodeIdUnknown

Endpoint: 'opc.tcp://opc-pc:48010'
Node: 'nsu=http://IBHsoftec.com/IBHLinkUA/;ns=4;s=OPC_UA_2017.Lijn3.Generic.TW2_WCS_Ist'

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support
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29 Aug 2017 17:16 #5459 by support

Replied by support on topic Trying to read OPC UA value with Delphi

Try to pass

DataDialog.NodeDescriptor.NodeId.ToString

as a 2nd argument to ReadValue instead.

The ToString method of the UANodeDecsriptor returns a string that is not in the right format.
I admit this is not very logical, as the 2nd argument is called 'nodeDescriptorString'. I will make a note and we will try to improve it in the future version.

Best regards

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eh
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29 Aug 2017 10:56 #5457 by eh

Trying to read OPC UA value with Delphi was created by eh

I'm trying to read a value from a tag on my OPC UA server.
Therefore I used following code, but I get an error(see attachment). What am I missing or doing wrong?

var Client: TEasyUAClient;
    Value: OleVariant;
    DataDialog: TUADataDialog;
    Endpoint, Node: string;
begin
  DataDialog := TUADataDialog.Create(nil);
  DataDialog.UserPickEndpoint := True;
  DataDialog.ShowDialog(nil);
 
  Endpoint := DataDialog.EndpointDescriptor.ToString;
  Node := DataDialog.NodeDescriptor.ToString;
 
  Client := TEasyUAClient.Create(nil);
 
  Value := Client.ReadValue(DataDialog.EndpointDescriptor.ToString, DataDialog.NodeDescriptor.ToString);
  cxtextedit3.Text := Value;
end;