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Variable info in delphi

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01 Aug 2017 15:30 #5400 by support
Replied by support on topic Variable info in delphi
  // Instantiate the client object
  Client := TEasyUAClient.Create(nil);
 
  ReadArguments1 := CoUAReadArguments.Create;
  ReadArguments1.EndpointDescriptor.UrlString := 'http://opcua.demo-this.com:51211/UA/SampleServer';
  ReadArguments1.NodeDescriptor.NodeId.ExpandedText := 'nsu=http://test.org/UA/Data/;i=10845';
  ReadArguments1.AttributeId := UAAttributeId_DisplayName;
 
  ReadArguments2 := CoUAReadArguments.Create;
  ReadArguments2.EndpointDescriptor.UrlString := 'http://opcua.demo-this.com:51211/UA/SampleServer';
  ReadArguments2.NodeDescriptor.NodeId.ExpandedText := 'nsu=http://test.org/UA/Data/;i=10845';
  ReadArguments2.AttributeId := UAAttributeId_ValueRank;
 
  ReadArguments3 := CoUAReadArguments.Create;
  ReadArguments3.EndpointDescriptor.UrlString := 'http://opcua.demo-this.com:51211/UA/SampleServer';
  ReadArguments3.NodeDescriptor.NodeId.ExpandedText := 'nsu=http://test.org/UA/Data/;i=10845';
  ReadArguments3.AttributeId := UAAttributeId_DataType;
 
  Arguments := VarArrayCreate([0, 2], varVariant);
  Arguments[0] := ReadArguments1;
  Arguments[1] := ReadArguments2;
  Arguments[2] := ReadArguments3;
 
  // Obtain values. By default, the Value attributes of the nodes will be read.
  TVarData(Results).VType := varArray or varVariant;
  TVarData(Results).VArray := PVarArray(Client.ReadMultipleValues(
    PSafeArray(TVarData(Arguments).VArray)));
 
  // Display results
  for I := VarArrayLowBound(Results, 1) to VarArrayHighBound(Results, 1) do
  begin
      Result := IInterface(Results[I]) as _ValueResult;
      WriteLn;
      WriteLn('Value: ', Result.Value);
  end;

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01 Aug 2017 14:35 #5399 by alr1976
Replied by alr1976 on topic Variable info in delphi
This is my function: I have always 'FromCache' result

procedure TFormBrowser.ReadAttribute(Attributeid: Integer);
var
Count: Cardinal;
Element: OleVariant;
EndpointDescriptor: _UAEndpointDescriptor;
NodeDescriptor: _UANodeDescriptor;
NodeElement: _UANodeElement;
NodeElementEnumerator: IEnumVariant;
NodeElements: _UANodeElementCollection;
tempendpoint,tempnode :string;
temp :TUAReadArguments;
tempread :_UAReadParameters;
begin


tempendpoint := 'opc.tcp://127.0.0.1:45320';
tempnode := 'nsu=KEPServerEX;ns=2;s=TEST.000000.COMANDO';
EndpointDescriptor := CoUAEndpointDescriptor.Create;
EndpointDescriptor.UrlString := tempendpoint;
NodeDescriptor := CoUANodeDescriptor.Create;
NodeDescriptor.NodeId.NamespaceUriString := tempnode;
temp := TUAReadArguments.Create(nil);
temp.EndpointDescriptor := EndpointDescriptor;
temp.NodeDescriptor := NodeDescriptor;
temp.AttributeId := Attributeid;
temp.Connect;
tempread := temp.ReadParameters;

showmessage(tempread.tostring);
end;

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01 Aug 2017 14:07 #5398 by alr1976
Replied by alr1976 on topic Variable info in delphi
Hi!

I m working on it but I don t have successfully read attributeid can you write a small example to read Attributeid in Delphi?

Thanks

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01 Aug 2017 11:21 #5397 by support
Replied by support on topic Variable info in delphi
In OPC UA, all nodes have multiple attributes. By default, QuickOPC works with the Value attribute. There are other attributes that contain additional information. You can specify an AttributeID in objects like UAReadParameters.

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01 Aug 2017 08:10 #5394 by alr1976
Hi!

How can I read variable info in Delphi?(Variable type,value,description and so on)

Thanks Alessandro

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