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Posted to dev@plc4x.apache.org by Gregor Minuge <gr...@sql-ag.de> on 2020/09/15 12:19:43 UTC

Problems with Read/Write using PLC4J OPC UA driver

Hi everyone,
I have two questions regarding the PLC4J OPC UA driver. I am connecting to the Eclipse Milo Server using the standard syntax as described here<https://plc4x.apache.org/users/protocols/opc-ua.html>.

1. I'm not able to read arrays (or their elements). All other data types work fine, but I don't understand how to add array fields as items to the readRequestBuilder. I'm either (obviously) getting a ClassCastException when I'm trying .additem(.../BooleanArray) or an PlcInvalidFieldException when trying to access a field of the array like addItem(...BooleanArray[0]).

The response.getObject(fieldName) call mentioned under the "Getting Started<https://plc4x.apache.org/users/plc4j/gettingstarted.html>" section on the website is not helping, because compilation already fails before getting the response.

If the reading of arrays is already implemented, could you please point me in the right direction here?

1. Likewise, I'm not able to write all data types. Apart from unsigned types, I'm having problems with Array, CustomStructTypeVariable, CustomUnionTypeVariable, AnalogValue, Object, Byte, ByteString, DateTime, Guid, QualifiedName, SByte, UtcTime, Variant and XmlElement.

I'm either getting an AccessDenied-error, probably because I'm trying to write the wrong data type to a field (which is especially strange for Byte), or a "java.lang.IllegalArgumentException: no field handler for class ... found" exception.

I could provide my code if needed, but as I'm generally following the suggested path for writing a writeRequest/Response, and it is working fine for simpler file types, I'd like to know whether these other types are already supported by the PLC4J library or not.
Lastly, if these features are not implemented in PLC4J, are there any plans to do so in the future, or would you recommend using Eclipse Milo to a wider extent, even if that meant neglecting the PLC4X-API in part? If it is the former and it would be appreciated, we could imagine helping you in your efforts.
Thanks for your time!
Best regards
Gregor Minuge

AW: Problems with Read/Write using PLC4J OPC UA driver

Posted by Gregor Minuge <gr...@sql-ag.de>.

Hi Milan,

thanks for the quick reply.

Of course I can show you my example code - I basically just modified Julian's code from https://github.com/pragmaticindustries/webinar-plc4x to try the read/write functionality of all data types present in the Eclipse Milo Server.
I hope the formatting of the mail doesn't look as awful again, my apologies if it does.

Best regards
Gregor Minuge


public class OpcDemo
{

   private static final Logger logger = LoggerFactory.getLogger( OpcDemo.class );

   public static void main( String[] args )
   {
      PlcDriverManager driverManager = new PlcDriverManager();

      try (PlcConnection connection = driverManager.getConnection( "opcua:tcp://127.0.0.1:12686/milo" ))
      {

         logger.info( "Verbindung ist aufgebaut..." );
         if( !connection.getMetadata().canWrite() )
         {
            logger.error( "This connection doesn't support writing." );
            return;
         }
		 
		 
         Boolean[] booleanArray = {true, true, true, true, true};

         CompletableFuture<? extends PlcWriteResponse> requestWriteFuture = connection.writeRequestBuilder()
                  .addItem( "Boolean", "ns=2;s=HelloWorld/ScalarTypes/Boolean", true ) // WORKS
                  .addItem( "Double", "ns=2;s=HelloWorld/ScalarTypes/Double", 3.15 ) // WORKS
                  .addItem( "Float", "ns=2;s=HelloWorld/ScalarTypes/Float", (float) 2.3 ) // WORKS		 
                  .addItem( "Int16", "ns=2;s=HelloWorld/ScalarTypes/Int16", (short) 15  ) // WORKS
                  .addItem( "Int32", "ns=2;s=HelloWorld/ScalarTypes/Int32", 64363 ) // WORKS
                  .addItem( "Int64", "ns=2;s=HelloWorld/ScalarTypes/Int64", (long) 513 ) // WORKS
                  .addItem( "Integer", "ns=2;s=HelloWorld/ScalarTypes/Integer", 432 ) // WORKS
                  .addItem( "SByte", "ns=2;s=HelloWorld/ScalarTypes/SByte", (byte) 2 ) // WORKS
                  .addItem( "String", "ns=2;s=HelloWorld/ScalarTypes/String", "helloWorld" ) // WORKS
                  .addItem( "StringWrite", "ns=2;s=HelloWorld/WriteOnly/String", "write" ) // WORKS

                  //.addItem( "BooleanArray", "ns=2;s=HelloWorld/ArrayTypes/BooleanArray", true ) //ClassCastException
				  //.addItem( "BooleanArray", "ns=2;s=HelloWorld/ArrayTypes/BooleanArray[0]", true ) //PlcInvalidFieldException
                  //.addItem( "BooleanArray", "ns=2;s=HelloWorld/ArrayTypes/BooleanArray", booleanArray ) //ACCES DENIED

                  //.addItem( "Bar", "ns=2;s=HelloWorld/MyObject/2:Bar", object ) //no field handler for class java.lang.Object found (but maybe my approach was too simple)
                  //.addItem( "DateTime", "ns=2;s=HelloWorld/ScalarTypes/DateTime", Instant.now()) //no field handler found (I also tried it with localdatetime and milliseconds)
				  //.addItem( "Duration", "ns=2;s=HelloWorld/ScalarTypes/Duration", (long) 1 ) //ACCESS DENIED (was playing around with that, "real" duration leads to PlcInvalidFieldException iirc)
                  //.addItem( "Guid", "ns=2;s=HelloWorld/ScalarTypes/Guid", UUID.randomUUID() ) //NO FIELD HANDLER FOUND
                  //.addItem( "LocalizedText", "ns=2;s=HelloWorld/ScalarTypes/LocalizedText", "localized" ) //ACCESS DENIED (probably needs some other format, but maybe not implemented?)
                  //.addItem( "NodeId", "ns=2;s=HelloWorld/ScalarTypes/NodeId", "{ns=1234, id=abcde}" ) //ACCESS DENIED
                  //.addItem( "QualifiedName", "ns=2;s=HelloWorld/ScalarTypes/QualifiedName", "{name=defg, namespaceIndex=1234}" ) //ACCESS DENIED (with or without braces)

                  //.addItem( "UtcTime", "ns=2;s=HelloWorld/ScalarTypes/UtcTime", Instant.now() ) //NO FIELD HANDLER FOUND
                  //.addItem( "Variant", "ns=2;s=HelloWorld/ScalarTypes/Variant", new Variant(32) ) //NO FIELD HANDLER FOUND
                  //.addItem( "XmlElement", "ns=2;s=HelloWorld/ScalarTypes/XmlElement",new Variant(new XmlElement("<a>hello</a>")) ) //NO FIELD HANDLER FOUND


                  .build().execute();
         logger.info( "Schreibanfrage gesendet..." );

         PlcWriteResponse writeResponse = requestWriteFuture.get();
         logger.info( "Antwort auf Schreibanfrage erhalten..." );

         //          Inspect response
         logger.info( "Antwort der Steuerung:" );
         for( String fieldName : writeResponse.getFieldNames() )
         {
            logger.info( "{} - {}", fieldName, writeResponse.getResponseCode( fieldName ) );
            if( writeResponse.getResponseCode( fieldName ) == PlcResponseCode.OK )
            {
               logger.info( "{} - {}", fieldName, writeResponse.getField( fieldName ) );
            }
         }

         // Send Read Request
         //
         // Everything except for arrays works fine
		 
         CompletableFuture<? extends PlcReadResponse> requestFuture = connection.readRequestBuilder()
				  //.addItem( "BooleanArray", "ns=2;s=HelloWorld/ArrayTypes/BooleanArray[0]" ) // PLCInvalidFieldException
                  //.addItem( "BooleanArray", "ns=2;s=HelloWorld/ArrayTypes/BooleanArray" ) // ClassCastException
                  //
                  .build()
                  .execute();
         //
         logger.info( "Anfrage gesendet..." );
         PlcReadResponse readResponse = requestFuture.get();
         logger.info( "Antwort erhalten..." );
         // Inspect response
         logger.info( "Antwort der Steuerung:" );
         for( String fieldName : readResponse.getFieldNames() )
         {
            logger.info( "{} - {}", fieldName, readResponse.getResponseCode( fieldName ) );
            if( readResponse.getResponseCode( fieldName ) == PlcResponseCode.OK )
            {
               logger.info( "{} - {}", fieldName, readResponse.getObject( fieldName ) );
            }
         }
      }

      catch(

               Exception e )
      {
         logger.error( "Konnte keine Verbindung aufbauen", e );
      }
   }
}




-----Ursprüngliche Nachricht-----
Von: Strljic, Matthias Milan <ma...@isw.uni-stuttgart.de> 
Gesendet: Mittwoch, 16. September 2020 15:20
An: dev@plc4x.apache.org
Betreff: AW: Problems with Read/Write using PLC4J OPC UA driver

Hi Gregor,

i will look for your issue to write/read the basic types and arrays. At the moment the support for custom/dynamic types is not included into the OPC UA integration. If you could provide me there some example code, we could try to find there a solution for or at least the information if it is intentionally not included 😊

Greetings Matthias
Matthias Strljic, M.Sc.

Universität Stuttgart
Institut für Steuerungstechnik der Werkzeugmaschinen und Fertigungseinrichtungen (ISW)

Seidenstraße 36
70174 Stuttgart
GERMANY

Tel: +49 711 685-84530
Fax: +49 711 685-74530

E-Mail: matthias.strljic@isw.uni-stuttgart.de
Web: http://www.isw.uni-stuttgart.de

-----Ursprüngliche Nachricht-----
Von: Gregor Minuge <gr...@sql-ag.de> 
Gesendet: Tuesday, September 15, 2020 2:20 PM
An: dev@plc4x.apache.org
Betreff: Problems with Read/Write using PLC4J OPC UA driver

Hi everyone,
I have two questions regarding the PLC4J OPC UA driver. I am connecting to the Eclipse Milo Server using the standard syntax as described here<https://plc4x.apache.org/users/protocols/opc-ua.html>.

  1.  I'm not able to read arrays (or their elements). All other data types work fine, but I don't understand how to add array fields as items to the readRequestBuilder. I'm either (obviously) getting a ClassCastException when I'm trying .additem(.../BooleanArray) or an PlcInvalidFieldException when trying to access a field of the array like addItem(...BooleanArray[0]).

The response.getObject(fieldName) call mentioned under the "Getting Started<https://plc4x.apache.org/users/plc4j/gettingstarted.html>" section on the website is not helping, because compilation already fails before getting the response.

If the reading of arrays is already implemented, could you please point me in the right direction here?



  1.  Likewise, I'm not able to write all data types. Apart from unsigned types, I'm having problems with Array, CustomStructTypeVariable, CustomUnionTypeVariable, AnalogValue, Object, Byte, ByteString, DateTime, Guid, QualifiedName, SByte, UtcTime, Variant and XmlElement.

I'm either getting an AccessDenied-error, probably because I'm trying to write the wrong data type to a field (which is especially strange for Byte), or a "java.lang.IllegalArgumentException: no field handler for class ... found" exception.

I could provide my code if needed, but as I'm generally following the suggested path for writing a writeRequest/Response, and it is working fine for simpler file types, I'd like to know whether these other types are already supported by the PLC4J library or not.
Lastly, if these features are not implemented in PLC4J, are there any plans to do so in the future, or would you recommend using Eclipse Milo to a wider extent, even if that meant neglecting the PLC4X-API in part? If it is the former and it would be appreciated, we could imagine helping you in your efforts.
Thanks for your time!
Best regards
Gregor Minuge

AW: Problems with Read/Write using PLC4J OPC UA driver

Posted by "Strljic, Matthias Milan" <ma...@isw.uni-stuttgart.de>.

Hi Gregor,

i will look for your issue to write/read the basic types and arrays. At the moment the support for custom/dynamic types is not included into the OPC UA integration. If you could provide me there some example code, we could try to find there a solution for or at least the information if it is intentionally not included 😊

Greetings Matthias
Matthias Strljic, M.Sc.

Universität Stuttgart
Institut für Steuerungstechnik der Werkzeugmaschinen und Fertigungseinrichtungen (ISW)

Seidenstraße 36
70174 Stuttgart
GERMANY

Tel: +49 711 685-84530
Fax: +49 711 685-74530

E-Mail: matthias.strljic@isw.uni-stuttgart.de
Web: http://www.isw.uni-stuttgart.de

-----Ursprüngliche Nachricht-----
Von: Gregor Minuge <gr...@sql-ag.de>
Gesendet: Tuesday, September 15, 2020 2:20 PM
An: dev@plc4x.apache.org
Betreff: Problems with Read/Write using PLC4J OPC UA driver

If the reading of arrays is already implemented, could you please point me in the right direction here?