OPC Foundation Message Board

RE: Java SDK properties of methods

Dirk D — Fri, 03 Jul 2009 14:22:07 GMT

Hi Otso,

your example seems to work. Thank you for that. But now I get an error in the client: The message decoding limits are exceeded (Bad_EncodingLimitsExceeded). I tried a few simple examples but nothing works. Do you have an idea?

Dirk

RE: Unable to create session

etan — Fri, 03 Jul 2009 14:00:09 GMT

OPC UA SDK 1.0.0 Sample Source Code (x86) 235.0 (Version: 1.0.0.23500)

the session endpoint of the client does not respond to my request. Maybe I am looking at the wrong configuration file?

RE: Unable to create session

Randy — Fri, 03 Jul 2009 13:23:55 GMT

Look in Add/Remove programs.

Find the installer that put the UA Sample Server on your system.

Check the Build Number.

RE: Unable to create session

etan — Fri, 03 Jul 2009 13:06:58 GMT

@i:nil
i:nil="true" instead of just an empty tag produces the same error.

Code:

@version number
When using the UA Sample Client of the big server and browsing to Objects\Server\ServerStatus\BuildInfo\SoftwareVersion it says 1.0

@sampleclient contains sampleserver
Will try to connect to this server later. Is this about the SimpleServer/Client or about the SDK (big server)?

RE: Unable to create session

Randy — Fri, 03 Jul 2009 12:54:50 GMT

One other possibility:

<ClientCertificate /> => new byte[0];
<ClientCertificate xsi:nil="true"> => null;

The new byte[0] causes an exception because the code checks for null.

RE: Unable to create session

Randy — Fri, 03 Jul 2009 12:41:37 GMT

What Build are you using for the Sample Server?

The trace I gave you was send to the Sample Server and it worked fine.

The SampleClient hosts the SampleServer within it. The code is identical the only thing that changes is the URLs.

RE: Unable to create session

etan — Fri, 03 Jul 2009 12:17:21 GMT

Your message won't work either

I've captured a message which was sent from the Big Sample Client to the no-security-endpoint of the Big Sample Server.

Differences to your sample are:

wsa:To header => Needed, but correct value is obvious

Code:

   <a:To s:mustUnderstand="1">
      http://opcua:51211/UA/SampleServer/None
   </a:To>
Other ApplicationUri and ServerUri and EndpointUrl => Obvious, since we don't use the same client/server

Code:

         <ApplicationUri>
            urn:192.168.0.1:61211:UA:SampleClient
         </ApplicationUri>

Code:

      <ServerUri>
         urn:opcua:51211:UA:SampleServer
      </ServerUri>

Code:

      <EndpointUrl>
         http://opcua:51211/UA/SampleServer/None
      </EndpointUrl>

The real problem: ClientNonce and ClientCertificate are specified. WHY? i thought that you won't need such things for a no-security-endpoint, as part 7 describes oO

Code:

      <ClientNonce>
         fX6BBhP3MXhNpqHr9iVKk+HP7ZZ3QW13GjkGdjQJmgg=
      </ClientNonce>
      <ClientCertificate>
         MIIC[...]cjs=
      </ClientCertificate>

Tried to insert the values of my original request / remove the additional values a:ReplyTo and a:MessageID. The only difference which holds me away from success is the clientNonce and clientCertificate

- are there bugs in the sample server code that it doesn't accept empty nonce or certificate values? where do I get a real securityMode: None server? Or could I insert just some dummy certificate and clientnonce?

RE: Unable to create session

etan — Fri, 03 Jul 2009 11:34:45 GMT

thanks for the fast answer. will compare this with my request.

RE: Java SDK properties of methods

Otso — Fri, 03 Jul 2009 10:06:28 GMT

Hello Dirk,

I took a look at your problem and tried to sort it out. Here are a couple of things that might solve your problem.

First, the BinaryEncoder needs a context to work in. In the code example below I used the default context, which can be obtained by calling EncoderContext.getDefault().

Second, the wrapped variable body can be used directly after encoding the Argument, though the Argument won't fit in such a small buffer. The example below will fit in a 57 byte array.

Here's an example that works (or at least it should...):

Code:

Argument arg = new Argument ("name",Identifiers.Int32,new Integer (-1),null,new LocalizedText ("an integer 32 value", Locale.ENGLISH));

byte [] body = new byte [57];

ByteBuffer buf = ByteBuffer.wrap(body);
buf.order(ByteOrder.LITTLE_ENDIAN);

BinaryEncoder binEncoder = new BinaryEncoder (buf);

binEncoder.setEncoderContext(EncoderContext.getDefault()); //setting the context for the Encoder
binEncoder.putStructure(new String(), arg);

// body = new byte[buf.capacity()]; //these are not really necessary
// buf.get(body, 0, body.length);

ExtensionObject extension = new ExtensionObject
(Identifiers.Argument_Encoding_DefaultBinary,body);

Variant value = new Variant(extension);

I hope this is of some help to you, let us know if you have further questions.

- Otso

RE: Unable to create session

Randy — Fri, 03 Jul 2009 09:57:48 GMT

The message above works

RE: Unable to create session

Randy — Fri, 03 Jul 2009 09:57:00 GMT

Code:

<s:Envelope xmlns:a="http://www.w3.org/2005/08/addressing" xmlns:s="http://www.w3.org/2003/05/soap-envelope">
<s:Header>
<a:Action s:mustUnderstand="1">http://opcfoundation.org/UA/2008/02/Services.wsdl/CreateSession</a:Action>
<a:MessageID>urn:uuid:4601af7f-842e-436a-add4-07bb559a66e6</a:MessageID>
<a:ReplyTo>
<a:Address>http://www.w3.org/2005/08/addressing/anonymous</a:Address>
</a:ReplyTo>
</s:Header>
<s:Body>
<CreateSessionRequest xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://opcfoundation.org/UA/2008/02/Types.xsd">
<RequestHeader>
<AuthenticationToken i:nil="true"></AuthenticationToken>
<Timestamp>2009-07-03T09:54:43.5794484Z</Timestamp>
<RequestHandle>1</RequestHandle>
<ReturnDiagnostics>1023</ReturnDiagnostics>
<AuditEntryId i:nil="true"></AuditEntryId>
<TimeoutHint>0</TimeoutHint>
<AdditionalHeader i:nil="true"></AdditionalHeader>
</RequestHeader>
<ClientDescription>
<ApplicationUri>urn:myhost:61211:UA:SampleClient</ApplicationUri>
<ProductUri>urn:opcfoundation.org:UA:SampleClient3</ProductUri>
<ApplicationName>
<Locale i:nil="true"></Locale>
<Text>UA Sample Client</Text>
</ApplicationName>
<ApplicationType>Client_1</ApplicationType>
<GatewayServerUri i:nil="true"></GatewayServerUri>
<DiscoveryProfileUri i:nil="true"></DiscoveryProfileUri>
<DiscoveryUrls></DiscoveryUrls>
</ClientDescription>
<ServerUri>urn:myhost:61211:UA:SampleClient</ServerUri>
<EndpointUrl>http://myhost:61211/UA/SampleClient/None</EndpointUrl>
<SessionName>MySession 1</SessionName>
<ClientNonce></ClientNonce>
<ClientCertificate></ClientCertificate>
<RequestedSessionTimeout>600000</RequestedSessionTimeout>
<MaxResponseMessageSize>4194304</MaxResponseMessageSize>
</CreateSessionRequest>
</s:Body>
</s:Envelope>

RE: Unable to create session

Randy — Fri, 03 Jul 2009 09:56:42 GMT

I really don't understand why it is giving you a stack trace but no exception message.

There should be comments in the sample client config file which turn on WCF tracing. You can using this to capture the messages sent by the sample client.

RE: Unable to create session

etan — Fri, 03 Jul 2009 09:17:16 GMT

The simpleServer you referred to contains only an endpoint with security, so it's not easy to get the messages (I only see the wsa-action in the captured traffic. The interesting rest is encrypted).

I've rechecked your second thought of the explanation for Bad being a null in a mandatory structure. In the following listings are my result, stating that everything seems to be fine.

According to Part 4 / 5.6.2.2, the createSession request takes the parameters:

requestHeader: part 4 / 7.26:
- authenticationToken: omitted (as 5.6.22 says)
- timestamp: 2009-06-05T07:45:00.649Z
- requestHandle: something other than 0: 2
- returnDiagnostics: 1023, representing all bits chosen
- auditEntryId: empty string = parameter not used (as 7.26 says)
- timoutHint: 0 (= no timeout, as 7.26 says)
- additionalHeader: omitted, since reserved for future use
clientDescription: part 4 / 7.1:
- applicationUri: client (identifier for the application instance)
- productUri: in this case empty, I've retried with 'product' but gives the same error: Bad (identifier for the product)
- applicationName: part 3 / 8.5:
  - text: Sample Client
  - locale: in this case empty, I've retried with 'en-US' but gives still same error
- applicationType: Client_1
- gatewayServerUri: omitted, since not used when applicationType is Client_1
- discoveryProfileUri: omitted, since not used when applicationType is Client_1
- discoveryUrls: omitted, since this field shall contain an empty list when applicationType is Client_1
serverUri: omitted, since this value is only specified if the endpointdescription has a gatewayserveruri
endpointUrl: http://opcua:51211/UA/SampleServer/None, the url where the whole request is sent to and which was specified by getEndpoints from the discovery endpoint
sessionName: omitted, the server shall assign a value
clientNonce: omitted, due to part 7
clientCertificate: omitted, due to part 7
RequestedSessionTimeout: 60000, okay as of part 3 / 8.13. represents 1 minute
maxResponseMessageSize: 0, the value zero indicates that this parameter is not used

So, everything seems to just be okay. I've also checked the types in the XSD-file and my values are conform to this file.

Is there some method to get a createSession message that works and which is not encrypted? Would help very much since I don't see any error in my message...

RE: Unable to create session

Randy — Fri, 03 Jul 2009 08:39:41 GMT

I recommend you download this sample:

http://www.opcfoundation.org/DownloadFile.aspx?CM=3&RI=518&CN=KEY&CI=288&CU=76

It contains a client and server built by ingesting the WSDL with WCF tools. It should help you analyze the difference between messages that work and the messages you are sending.

An error code if Bad means an unexpected exception occured. Most likely because a null was passed for a mandatory structure.

Unfortunately, nothing jumps out at me as being obviously wrong.

RE: Unable to create session

etan — Fri, 03 Jul 2009 07:57:43 GMT

Code:

                     <AdditionalInfo>
                        &gt;&gt;&gt; Bad&amp;#xD;
--- at Opc.Ua.Server.StandardServer.CreateSession(RequestHeader requestHeader, ApplicationDescription clientDescription, String serverUri, String endpointUrl, String sessionName, Byte[] clientNonce, Byte[] clientCertificate, Double requestedSessionTimeout, UInt32 maxResponseMessageSize, NodeId&amp; sessionId, NodeId&amp; authenticationToken, Double&amp; revisedSessionTimeout, Byte[]&amp; serverNonce, Byte[]&amp; serverCertificate, EndpointDescriptionCollection&amp; serverEndpoints, SignedSoftwareCertificateCollection&amp; serverSoftwareCertificates, SignatureData&amp; serverSignature, UInt32&amp; maxRequestMessageSize)&amp;#xD;
--- at Opc.Ua.SessionEndpoint.CreateSession(IServiceRequest incoming)&amp;#xD;
--- at Opc.Ua.EndpointBase.ServiceDefinition.Invoke(IServiceRequest request)&amp;#xD;
--- at Opc.Ua.EndpointBase.ProcessRequestAsyncResult.OnProcessRequest(Object state)
                     </AdditionalInfo>
                     <InnerStatusCode>
                        <Code>
                           0
                        </Code>
                     </InnerStatusCode>
                     <InnerDiagnosticInfo i:nil="true"/>
                  </InnerDiagnosticInfo>
               </ServiceDiagnostics>
               <StringTable/>
               <AdditionalHeader i:nil="true"/>
            </ResponseHeader>
         </ServiceFault>
      </s:Detail>
   </s:Fault>
</s:Body>
</s:Envelope>

RE: Unable to create session

etan — Fri, 03 Jul 2009 07:55:05 GMT

Reply doesn't fit in the last post, so I try it in a separate post:

Code:

               <ServiceDiagnostics>
                  <SymbolicId>
                     -1
                  </SymbolicId>
                  <NamespaceUri>
                     -1
                  </NamespaceUri>
                  <Locale>
                     -1
                  </Locale>
                  <LocalizedText>
                     -1
                  </LocalizedText>
                  <AdditionalInfo>
                     &gt;&gt;&gt; Bad&amp;#xD;
--- at Opc.Ua.EndpointBase.ProcessRequestAsyncResult.WaitForComplete(IAsyncResult ar, Boolean throwOnError)&amp;#xD;
--- at Opc.Ua.SessionEndpoint.EndCreateSession(IAsyncResult ar)&amp;#xD;
&amp;#xD;
&gt;&gt;&gt; Bad&amp;#xD;
--- at Opc.Ua.Server.StandardServer.CreateSession(RequestHeader requestHeader, ApplicationDescription clientDescription, String serverUri, String endpointUrl, String sessionName, Byte[] clientNonce, Byte[] clientCertificate, Double requestedSessionTimeout, UInt32 maxResponseMessageSize, NodeId&amp; sessionId, NodeId&amp; authenticationToken, Double&amp; revisedSessionTimeout, Byte[]&amp; serverNonce, Byte[]&amp; serverCertificate, EndpointDescriptionCollection&amp; serverEndpoints, SignedSoftwareCertificateCollection&amp; serverSoftwareCertificates, SignatureData&amp; serverSignature, UInt32&amp; maxRequestMessageSize)&amp;#xD;
--- at Opc.Ua.SessionEndpoint.CreateSession(IServiceRequest incoming)&amp;#xD;
--- at Opc.Ua.EndpointBase.ServiceDefinition.Invoke(IServiceRequest request)&amp;#xD;
--- at Opc.Ua.EndpointBase.ProcessRequestAsyncResult.OnProcessRequest(Object state)
                  </AdditionalInfo>
                  <InnerStatusCode>
                     <Code>
                        2147483648
                     </Code>
                  </InnerStatusCode>
                  <InnerDiagnosticInfo>
                     <SymbolicId>
                        -1
                     </SymbolicId>
                     <NamespaceUri>
                        -1
                     </NamespaceUri>
                     <Locale>
                        -1
                     </Locale>
                     <LocalizedText>
                        -1
                     </LocalizedText>

Unable to create session

etan — Fri, 03 Jul 2009 07:53:35 GMT

Hi,

I'm currently building a UA client from scratch to access a session endpoint with securityMode: None.

The GetEndpoint service from the discovery Endpoint gives me the URI for securityMode None; according to part 7, the server supports 'Security None CreateSession ActivateSession' which means that I don't have to send a clientCertificate and clientNonce when calling the createSession service.

However, when I actually try to create the session, I get returned an errorCode 'Bad', which I don't understand. Is there something wrong in the request? Do I have to send some other message before sending a createSession request?

The only and whole request I am sending to the server is:

Code:

<s:Envelope xmlns:s="http://www.w3.org/2003/05/soap-envelope" xmlns:a="http://www.w3.org/2005/08/addressing">
<s:Header>
   <a:Action s:mustUnderstand="1">
      http://opcfoundation.org/UA/2008/02/Services.wsdl/CreateSession
   </a:Action>
   <a:To s:mustUnderstand="1">
      http://opcua:51211/UA/SampleServer/None
   </a:To>
</s:Header>
<s:Body>
   <CreateSessionRequest xmlns="http://opcfoundation.org/UA/2008/02/Types.xsd">
      <RequestHeader>
         <AuthenticationToken/>
         <Timestamp>
            2009-06-05T07:45:00.649Z
         </Timestamp>
         <RequestHandle>
            2
         </RequestHandle>
         <ReturnDiagnostics>
            1023
         </ReturnDiagnostics>
         <AuditEntryId/>
         <TimeoutHint>
            0
         </TimeoutHint>
         <AdditionalHeader/>
      </RequestHeader>
      <ClientDescription>
         <ApplicationUri>
            client
         </ApplicationUri>
         <ProductUri/>
         <ApplicationName>
            <Locale/>
            <Text>
               Sample Client
            </Text>
         </ApplicationName>
         <ApplicationType>
            Client_1
         </ApplicationType>
         <GatewayServerUri/>
         <DiscoveryProfileUri/>
         <DiscoveryUrls/>
      </ClientDescription>
      <ServerUri/>
      <EndpointUrl>
         http://opcua:51211/UA/SampleServer/None
      </EndpointUrl>
      <SessionName/>
      <ClientNonce/>
      <ClientCertificate/>
      <RequestedSessionTimeout>
         60000
      </RequestedSessionTimeout>
      <MaxResponseMessageSize>
         0
      </MaxResponseMessageSize>
   </CreateSessionRequest>
</s:Body>
</s:Envelope>

The response I get is:

Code:

<s:Envelope xmlns:s="http://www.w3.org/2003/05/soap-envelope" xmlns:a="http://www.w3.org/2005/08/addressing">
<s:Header>
   <a:Action s:mustUnderstand="1">
      http://opcfoundation.org/UA/2008/02/Services.wsdl/CreateSessionFault
   </a:Action>
</s:Header>
<s:Body>
   <s:Fault>
      <s:Code>
         <s:Value xmlns:a="http://opcfoundation.org/UA/">
            a:Bad
         </s:Value>
      </s:Code>
      <s:Reason>
         <s:Text xml:lang="">
            Bad
         </s:Text>
      </s:Reason>
      <s:Detail>
         <ServiceFault xmlns="http://opcfoundation.org/UA/2008/02/Types.xsd" xmlns:i="http://www.w3.org/2001/XMLSchema-instance">
            <ResponseHeader>
               <Timestamp>
                  2009-07-03T07:43:54.8891488Z
               </Timestamp>
               <RequestHandle>
                  2
               </RequestHandle>
               <ServiceResult>
                  <Code>
                     2147483648
                  </Code>
               </ServiceResult>

RE: Java SDK properties of methods

Randy — Thu, 02 Jul 2009 16:04:14 GMT

I will see if I can get one of the developers who worked on the Java stack to look at the issue.

RE: DA version of the server

Randy — Thu, 02 Jul 2009 16:03:08 GMT

The only safe way is to request the v3.0 interface and try to use it. If you get an unexpected error the server does not support the v3.0 feature in question.

DA version of the server

Celestion — Thu, 02 Jul 2009 15:59:09 GMT

Hello,

How to get DA version supported by the server ?
Some programs are able to retrieve it but from where ?
I haven't found.

Thanks

Sorry for my english.

RE: Java SDK properties of methods

Dirk D — Thu, 02 Jul 2009 11:59:42 GMT

Hi,

I tried to serialize the argument and used the putStructure Method of the BinaryEncoder but this didn�t work. How can I serialize an argument in Java with BinaryEncoder?

Code:

Argument arg = new Argument (name,Identifiers.Int32,new Integer (-1),null,new LocalizedText ("an integer 32 value", Locale.ENGLISH));

byte [] body = new byte [10];

ByteBuffer buf = ByteBuffer.wrap(body);
buf.order(ByteOrder.LITTLE_ENDIAN);

BinaryEncoder binEncoder = new BinaryEncoder (buf);

binEncoder.putStructure(null, args);

body = new byte[buf.capacity()];
buf.get(body, 0, body.length);

ExtensionObject extension = new ExtensionObject
(Identifiers.Argument_Encoding_DefaultBinary,body);

Variant value = new Variant(extension);

RE: Java SDK properties of methods

Randy — Wed, 01 Jul 2009 18:56:06 GMT

The C# stack is able to serialize the built in types automatically if they are added to an ExtensionObject. The Java stack may not support this feature.

In that case you will have to manually serialize the argument.

The code in C# illustrates the steps and the Java stack is supposed to have equivalent APIs:

Code:

// initialize object.
Argument argument = new Argument();
argument.Name = "Hello";
argument.DataType = DataTypeIds.String;

// encode it with the UA binary encoding.
BinaryEncoder encoder = new BinaryEncoder(context);
encoder.WriteEncodeable(null, argument, null);
byte[] body = encoder.CloseAndReturnBuffer();

// wrap it in an extension object which also specifies that the body is an Argument structure encoded in UA binary.
ExtensionObject extension = new ExtensionObject(ObjectIds.Argument_Encoding_DefaultBinary, body);

// create an array.
ExtensionObject[] extensions = new ExtensionObject { extension };

// wrap in variant.
Variant value = new Variant(extensions);

RE: Java SDK properties of methods

Dirk D — Wed, 01 Jul 2009 12:44:17 GMT

OK. I have to put an array of ExtensionObjects into the Variant. But how do I put an Argument in an ExtensionObject?

For example:

Code:

Argument arg = new Argument (name,Identifiers.Int32,new Integer (-1),null,new LocalizedText ("an integer 32 value", Locale.ENGLISH));

ExtensionObject extension = new ExtensionObject (nodeID);

Variant value = new Variant(extension);

The last line in your example isn�t right, is it? I thought it would be:
Variant value = new Variant(extensions); without [ii].

RE: DCOM register timeout

JJ Flynn — Wed, 01 Jul 2009 10:56:08 GMT

As I mentioned in my original post, I'm not OPC literate. So, here's a portion of the report submitted by the outside contractor that got it working:

A Casepacker ( with an ELAU PLC) was added to the packaging line - there were a series of subsequent communication issues between the TrakSYS software (OPC communication) to ELAU OPC Server installed on the local computer.

The ELAU OPC Server (CoDeSys OPC Server version 2.3.11.0) was moved to a new computer on the packaging line in hopes of fixing some issues the original PC was experiencing and thought to be related to the installed ELAU software. The new computer was configured with DCOM settings to allow OPC Server with access and launch/activation permissions - STILL will no success.

Solution: New architecture - ELAU OPC Server installed on the TRAKSYS server that contains the plant database and (ELAU) EPAS-4 Gateway Server version 2.3.5.3 installed on the new PC (mentioned above) to act as a data gateway between the local plc network and the plant network.

This will also allow future ELAU PLCs OPC data to be added to TrakSYS with just the addition of the gateway server on the local plc area network and configuration of the ELAU OPC Server on main TRAKSYS server.

Security Audit Logon/Logoff event on an OPC Server

hqp — Tue, 30 Jun 2009 18:28:21 GMT

I have an application that use OPC RDI service to read data from an OPC Server. The application is set to read data every 5 min. In the Event Viewer of the OPC Server, we see a Success Audit with the Category Logon/Logoff for the user account (which runs the OPC RDI service) about twice per min (or about 30 sec frequency). Is this the normal frequency for OPC DCOM authentication? If it is, is it adjustable? If it it not, anyone knows why this is happening?

Thank you for your feedback/advice!

RE: Building the address space in the DataAccessServer solution

Randy — Tue, 30 Jun 2009 16:18:40 GMT

You can create the BlockState without the tags.
You would then use the BlockBrowser to find the tags.
This is the way the Segments work.

The ObjectTypes are defined by the ULS.

The StartSimulation starts a simulation of a system. You would not use it if you have a real system.

RE: [238.1] : unable to add Organizes ref. to Objects folder

Randy — Tue, 30 Jun 2009 16:12:17 GMT

Adding the reference from the ObjectFolder is the first step.

You need to also make sure the GetManagerHandle method recognizes your Node. The A&C quickstart was designed to access dynamic nodes in the system so it does not check the PredefinedNodes dictionary by default.

You will need to add that PredefinedNodes look up yourself.

RE: Building the address space in the DataAccessServer solution

NewbieOPC — Tue, 30 Jun 2009 16:03:32 GMT

Thank you for your answer Randy!
But what about the problem that the tags have to be created by a UnderlyingSystemBlock but the BlockBrowser has to operate on BlockState objects? I have problems to understand where and how to define the tags...

Sth. else: In one of your last post you told me:

Quote:

The mapping to the UA type refers to the UA Type Definition. If you have a set of tags that appears over and over again in different blocks you would likely want to create some ObjectTypes for the different Block types.

Are these ObjectTypes that one you specified in the s_BlockDatabase or do you mean sth. else?

By the way... What ist the purpose of the StartSimulation() method in the Underlying system? Do I have to modify it when the data comes from a real ULS?

RE: Objects vs ObjectTypes

Randy — Tue, 30 Jun 2009 15:12:18 GMT

Quote:

Why does Node 5 reference Node 293?

I thought you were wondering about 263.

Node 293 exists because the BoilerType may override some elements of the FlowTransmitter1.

For example, the BoilerType could add an EngineeringUnits to the Output (Node 294).

RE: Inconsistencies in the Boiler sample

Randy — Tue, 30 Jun 2009 15:05:50 GMT

Quote:

the number of instances is fixed, the number of instance nodes is in O(n). The number of nodes used to define the structure, however, is in O(n^2).

Only if you insist on modelling it that way. You can model each instance with a single type of of N nodes if that makes more sense to you.

RE: Building the address space in the DataAccessServer solution

Randy — Tue, 30 Jun 2009 15:03:29 GMT

Quote:

In the SegmentBrowser you assume that you already have the structure of the block paths stored in "s_BlockPathDatabase". Does that mean that I need a DB like this for the tags as well? I think I need some mechanism that tells the UPC UA Server which tags belong to which block.

Exactly. If you don't know the tags in advance your system must provide a way to look up what tags exists when passed a Block identifier.

Quote:

How can I construct an ID for an Tag??

However you want. You need to store enough information that would allow you to look up a tag in the system. This implies that each tag has a unique id which can be used to look up the tag metadata from the ULS.

RE: Inconsistencies in the Boiler sample

Banjobeni — Tue, 30 Jun 2009 14:58:46 GMT

Assume you have fixed number of structurally identical instances, each of them having n nodes. These n nodes are arranged in a linked-list like order as in the biooer (subpart). Now you want to provide metadata for those structures.

Since the number of instances is fixed, the number of instance nodes is in O(n). The number of nodes used to define the structure, however, is in O(n^2).

RE: Java SDK properties of methods

Randy — Tue, 30 Jun 2009 14:51:32 GMT

You need to put an array of ExtensionObjects into the Variant even if you only have one argument.

In C# the code would look like this:

Code:

ExtensionObject[] extensions = new ExtensionObject[args.Length];

for (int ii =0; ii < args.Length; ii++)
{
extensions[ii] = new ExtensionObject(args[ii]);
}

Variant value = new Variant(extensions[ii]);

RE: Inconsistencies in the Boiler sample

Randy — Tue, 30 Jun 2009 14:47:33 GMT

Quote:

My point is still valid. If you are not going to reuse existing types, which can easily be the case when you have a non-common setup, you need in the order of n^2 nodes only to provide metadata for n nodes.

No it is not because you would never create those additional types if you do not re-use them. Types that are not re-used have no value from a semantic or structural point of view.

Consider the example of a Person table in a SQL data base. You could model a Person by creating a seperate Address table that is referenced by a foreign key in the Person table. However, such a model would be a waste of time if the Address table is not referenced by any other table. On the other hand, such a model is very appropriate if you have another table called Company which also includes an Address with the same fields.

You should not view information models as a 'one size fits all' proposition. Different people with different requirements will use the model in different ways.

RE: Objects vs ObjectTypes

Banjobeni — Tue, 30 Jun 2009 14:41:06 GMT

Okay, you are right.

Let me state the question differently then: Why does Node 5 reference Node 293?

After all, node 5 is only a bucket to provide the name of the virtual reference from node 4 to node 262. That means to me that the only outgoing reference from node 5 should be the HasTypeDefinition to node 262.

[238.1] : unable to add Organizes ref. to Objects folder

frsauvage — Tue, 30 Jun 2009 14:39:48 GMT

Hi,
I'm trying to add dynamically an object (derived from FolderState) to the "Objects" folder root

I have begun with the Alarm and Condition Server sample (238.1). I created a "DeviceGroupType" in a model and I complied it to "DeviceGroupState" class.

Here is my code :
public override void CreateAddressSpace(IDictionary<NodeId, IList<IReference>> externalReferences)
{
base.CreateAddressSpace(externalReferences);
lock (Lock)
{
IList<IReference> references = null;
externalReferences[Opc.Ua.ObjectIds.ObjectsFolder] = references = new List<IReference>();

ushort index = (ushort)Server.NamespaceUris.GetIndex(Canberra.Ua.NodeManager.Model.CanberraDevices.Namespaces.OPCUACanberraDevices);
string folderPath = Utils.Format("{0}/{1}", String.Empty, "myFolder");
NodeId folderId = ModelUtils.ConstructIdForArea(folderPath, index);
DeviceGroupState devicegroupinstance = new DeviceGroupState(null);
devicegroupinstance.Create(SystemContext, folderId, new QualifiedName(browseName, index), new LocalizedText(displayName), true);
// add a reference link from Objects main folder
Server.CoreNodeManager.AddReference(Opc.Ua.ObjectIds.ObjectsFolder,
Opc.Ua.ReferenceTypeIds.Organizes, false, devicegroupinstance.NodeId, false);
AddPredefinedNode(this.SystemContext, devicegroupinstance);
// add an organizes reference from the ObjectsFolder to the area.
references.Add(new NodeStateReference(Opc.Ua.ReferenceTypeIds.Organizes, false, folderDeviceGroup.NodeId));
...

I don't know how to add a simple "Organizes" reference to an object from the "Objects" folder of the Server, where am I wrong

This code worked with 237 version in the OnNodeManagerStarted.

RE: opc newbie

Fred_Loveless — Tue, 30 Jun 2009 14:37:30 GMT

Right now many of the early adopters are scrambling to get OPC UA products out the door. Iconics and Kepware Partnered to provide an OPC UA soluiton using Iconics Genesis64 and Kepware Kepserver for Iconics. Kepware also partnered with Unified Automation(http://www.opcfoundation.org/Products/ProductDetails.aspx?CM=1&RI=8956&CU=87http://www.opcfoundation.org/Products/ProductDetails.aspx?CM=1&RI=8956&CU=87) to provide OPC UA. Unified Automation has a sample client that can run on Linux platforms.

I think you will see that the major vendors will come out with OPC UA products for windows in the next year and that depending on the complexity Linux will follow that. The big decodomg factor for Linux support will be the demand that the ROI for the companies developing solutions.

Fred Loveless
Senior Application Engineer
Kepware Technoligies

RE: Objects vs ObjectTypes

Randy — Tue, 30 Jun 2009 14:32:40 GMT

Quote:

I do not concern about reality. But i do concern about models. So my statement is that I dont understand why the FlowTransmitter1 (the one with NodeId 293) is present.

I answered your question twice now:

Hypothetically, the Node is used by other types in the model which are not shown. You cannot assume that a node is not used simply because it does not appear to be used within the subset of the model that you have choosen to highlight.

I gave examples of why it could be used in other parts of the information model.

RE: Building the address space in the DataAccessServer solution

NewbieOPC — Tue, 30 Jun 2009 14:23:22 GMT

Hi Randy!

I started to build up the BlockBrowser but I have to solve some problems. I hope you can give me some advice how to continue.

My questions are those:

1.) Isnt it the case that I have to create the tags before I can start browsing them (i.e. use the CreateTag() method on a UnderLyingSystemBlock element)? As far as I understood, the UnderlyingSystemBlock and its UnderlyingSystemTags need to be specified BEFORE I map them to OPC UA confirm objects by using the BlockState class: The BlockBrowser which I have to implement has to be based on a BlockState object. This BlockState object will be build out of an UnderlyingSystemBlock (and his tags) => The tags need to be specified before the BlockBrowser can operate on the BlockState object. Otherwise I see no possibility to create the tags during browsing because only the UnderlyingSystemBlock can add tags. The BlockState object can not...

2.) In the SegmentBrowser you assume that you already have the structure of the block paths stored in "s_BlockPathDatabase". Does that mean that I need a DB like this for the tags as well? I think I need some mechanism that tells the UPC UA Server which tags belong to which block. I am thinking about implementing a class that browses the real ULS and delivers two information to the opc ua server: A DB like s_BlockPathDatabase which delivers all known block paths and a database which contains objects that describe the tags (i.e.: their name, datatype, value,...) that belong to the each specific block in the ULS.

Truly speaking, it is not clear to me if this is the right way to go?

3.) Should the BlockBrowser be similar to the SegmentBrowser? There you use ConstructIdForBlock and ConstructIdForSegements? How can I construct an ID for an Tag??

I hope you can give me some suggestions how to build up this BlockBrowser. It would be important to know: What information the OPC UA server needs from the ULS in order to create the tags (when the tags belonging to a block are not implied by the block type but have to be read from the ULS for each block instead), how the tags can be created afterwards and what the BlockBrowser has to do in this context exactly.

Sorry for all that questions
Kind regards!

Java SDK properties of methods

Dirk D — Tue, 30 Jun 2009 11:30:48 GMT

Hi,

I want to describe a method�s input and output arguments using properties.
The value of each property should be an Argument object which stores name, data type, value rank, array dimension and description. To set the value of each property I wanted to put the Argument object in a Variant object, but this didn�t work. I tried it with the ExtensionObject class but it didn�t work either.
How can I define the input and output arguments of a method properly?