//First procedure ->

procedure TOPCClient.Connect;
begin
  Meldung(0,'TOPCClient.Connect');
  SollConnect := TRUE;
  InternConnect;
end;

procedure TOPCClient.InternConnect;
Var
Name, NodeID : String;
I,J : Integer;
SubscribeChangeClient: TEasyUAClient;
MonitoringParameters: _UAMonitoringParameters;
MonitoredItemArguments : Array of _EasyUAMonitoredItemArguments;
SubscribeArguments: OleVariant;
HandleArray: OleVariant;

begin
  InternDisconnect;
  Meldung(0,'TOPCClient.InternConnect');

  try
    ///  OPC UA Server verbinden
    OPCUAClient := TEasyUAClient.Create(nil);
    OPCUAClientSPS := TEasyUAClient.Create(nil);
    OPCUAClientRead := CoEasyUAClient.Create;
    OPCUAClientSPS.SubscribeDataChange(Url_String,'nsu='+ nsu + ';s=' + S0 ,1000);
(*!!!!!Start of commenting out
    SubscribeChangeClient := TEasyUAClient.Create(nil);

    SetLength(MonitoredItemArguments,Length(OPCServerItemArray)-NoV_DB100);
    MonitoringParameters := CoUAMonitoringParameters.Create;
    MonitoringParameters.SamplingInterval := 1000;

    for J := NoV_DB100 to Length(OPCServerItemArray)-1 do begin
       Name := OPCServerItemArray[J].Source + '.' + OPCServerItemArray[J].ItemName;
       MonitoredItemArguments[J-NoV_DB100] := CoEasyUAMonitoredItemArguments.Create;
       MonitoredItemArguments[J-NoV_DB100].EndpointDescriptor.UrlString := Url_String;
       MonitoredItemArguments[J-NoV_DB100].NodeDescriptor.NodeId.ExpandedText := 'nsu='+ nsu + ';s=Local Items.' + Name;
       MonitoredItemArguments[J-NoV_DB100].MonitoringParameters := MonitoringParameters;

    end;

    SubscribeArguments := VarArrayCreate([0, Length(OPCServerItemArray)-NoV_DB100-1], varVariant);
    for I := 0 to Length(OPCServerItemArray)-NoV_DB100-1 do begin
       SubscribeArguments[I] := MonitoredItemArguments[I];
    end;

    TVarData(HandleArray).VType := varArray or varVariant;
    TVarData(HandleArray).VArray := PVarArray(
    SubscribeChangeClient.SubscribeMultipleMonitoredItems(PSafeArray(TVarData(SubscribeArguments).VArray)));

End of commenting out!!!!!*)
   
    OPCUAClient.Connect;
    OPCUAClientSPS.Connect;
    Connected := TRUE;
    Meldung(0,'TOPCClient.InternConnect - Done!');
  except
    on E: Exception do begin
      Meldung(0,'TOPCClient.InternConnect: Connecting to OPC UA Server (FAILED: ' + E.Message + ')');
      InternDisconnect;
    end;
  end;

end;


//Second procedure ->

Procedure TOPCClient.ReadSPSItems;
 var
 ReadVar_vonSPS : Array of OleVariant;
 AttributeSPSData : UAAttributeData;
 I: Integer;
 ItemRead : Boolean;
 Name : String;
 ReadOPCUAArguments : Array of _UAReadArguments;
 OPCUAResult: _UAAttributeDataResult;
 OPCUAResults: OleVariant;
 OPCUAArguments : OleVariant;
 J,K: Cardinal;
 begin

   ItemRead := False;
   try

     if (Connected) then begin

        AttributeSPSData := OPCUAClientSPS.Read(Url_String,'nsu='+ nsu + ';s=' + S0);
        ReadVar_vonSPS := AttributeSPSData.Value;
        for I := 0 to NoV_DB100-1 do begin
           OPCServerItemArray[I].Value    := ReadVar_vonSPS[I];
           OPCServerItemArray[I].ItemQuality := AttributeSPSData.StatusCode;
           OPCServerItemArray[I].TimeStamp := AttributeSPSData.ServerTimestamplocal;
           //showmessage('VarNo='+IntToStr(I)+ ' Value=' +VarToStr(OPCServerItemArray[I].Value)+ ' Quality=' + VarToStr(AttributeSPSData.StatusCode) + ' Time=' +  VarToStr(AttributeSPSData.ServerTimestamp));
        end;
(*!!!!!Start of commenting out
        SetLength(ReadOPCUAArguments,Length(OPCServerItemArray)-NoV_DB100);

        for J := NoV_DB100 to Length(OPCServerItemArray)-1 do begin
           Name := OPCServerItemArray[J].Source + '.' + OPCServerItemArray[J].ItemName;
           ReadOPCUAArguments[J-NoV_DB100] := CoUAReadArguments.Create;
           ReadOPCUAArguments[J-NoV_DB100].EndpointDescriptor.UrlString := Url_String;
           ReadOPCUAArguments[J-NoV_DB100].NodeDescriptor.NodeId.ExpandedText := 'nsu='+ nsu + ';s=Local Items.' + Name;
        end;

        OPCUAArguments := VarArrayCreate([0, Length(OPCServerItemArray)-NoV_DB100-1], varVariant);
        for I := 0 to Length(OPCServerItemArray)-NoV_DB100-1 do begin
           OPCUAArguments[I] := ReadOPCUAArguments[I];
        end;
       
        TVarData(OPCUAResults).VType := varArray or varVariant;
        TVarData(OPCUAResults).VArray := PVarArray(OPCUAClientRead.ReadMultiple(
        PSafeArray(TVarData(OPCUAArguments).VArray)));
        // Writing the results in Delphi internal Array
        for K := VarArrayLowBound(OPCUAResults, 1) to VarArrayHighBound(OPCUAResults, 1) do
        begin
           OPCUAResult := IInterface(OPCUAResults[K]) as _UAAttributeDataResult;
           OPCServerItemArray[NoV_DB100+K].Value    := OPCUAResult.AttributeData.value;
           OPCServerItemArray[NoV_DB100+K].ItemQuality := OPCUAResult.AttributeData.StatusCode;
           OPCServerItemArray[NoV_DB100+K].TimeStamp := OPCUAResult.AttributeData.ServerTimestamplocal;         
        end;
End of commenting out!!!!!*)

     end else begin
         Meldung(0,'TOPCClient.ReadSPSItems: ' + ' (Not connected to the OPC UA Server!)');
     end;

   except
    on E: Exception do begin
      Meldung(0,'TOPCClient.ReadSPSItems - Exception: ' + E.Message);
    end;

   end;

 end;