Subscribtion to server items

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CarstenW
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Subscribtion to server items

Post by CarstenW »

Hi Support-Team,

currently I am evaluating your software solution UaGateway for our purposes.

In our project we have to access an old OPC XML DA Server via OPC UA. So I configured the
gateway and also the XML DA location. Now I am able to browse the local UA server with a demo client.
I can see all items on the XML DA server but I can not subscribe to any. If I try a subscription, I get the following error output:

BadAttributeIdInvalid
Id: BadAttributeIdInvalid

It is possible to subscribe the items generated by the UA server like
Objects.Server.ServerArray but no item from the XML DA server.

Any ideas?

Best regards
Carsten

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Re: Subscribtion to server items

Post by Support Team »

Hello Carsten,

when configuring the connection to the XML Server, it should say "connected" in the ConfigTool. You than can give it a test using UaExpert. Connect to the UaGateway and browse into the tree of nodes. Find the root entry point of the underlying XML Server below the "Objects" and browse into it (the entry point has the name you have given it during configuration of the connection). If you can see the nodes from the underlying server the connection is just fine.

If you click on a node in the tree the UaExperts "Attribute Window" will perform an explicite "Read" on that particular node and all its attibutes including the value. Are there any errors reported on this "Read" already? Can you see the value in the AttributeWindow?

Second step is to "Subscribe" this node. You "Drag&Drop" it into the "DA-View"-pane of the UaExpert and the node will be subscribed. Check the LogWindow of the UaExpert for any errors on "CreateMonitoredItems". If you not getting updates, please check if the value is moving in real life.

We have tested with XML-DA Reference Server from OPC Foundation and it works like a charm.

Which attribute are you trying to read? What UA Client are you using? Can you create subscription on this XML Server using a "pure" XML-DA Client (e.g. the one available at the OPC Foundation)?

Best Regards
Support Team

CarstenW
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Re: Subscribtion to server items

Post by CarstenW »

Hello Support-Team,

first thank you for the fast reply.
Here is a summary of the current behavior.

1:
I can browse the XML-DA Server with dOPCExplorer without any issues. I am able to subscripe to any item on this server and get live updates.

2:
The UA Wrapper works fine. The underlying XML DA server is "connected". In the properties for the underlying server, the user and password
to get access to the XML-DA server is set and "stored".

3:
Using the UA Expert or any other UA Client, it is possible to browse the underlying XML-DA server. I can browse all items without any issues.

4:
If one item is selected within the UA Client, the attribute panel gives the following output (example for one item):
NodeId - NodeId
NamespaceIndex=4
IdentifierType=String
Identifier=opc_heartbeat01.heartbeat-data.ticks
NodeClass - Variable
BrowseName=4,"opc_heartbeat01.heartbeat-data.ticks"
DisplayName="","opc_heartbeat_01.heartbeat-data.ticks"
Description: BadInvalidArgument(0x80ab0000)
WriteMask=0
UserWriteMask=0
Value
SourceTimestamp=01.01.1601 01:00:00.000
SourcePicoseconds=0
ServerTimestamp=04.07.2014 10:12:15.621
ServerPicoseconds=0
StatusCode=Bad(0x80000000)
Value=Null
DataType - BaseDataType
NamespaceIndex=0
IdentifierType=Numeric
Identifier=24
ValueRank=-1
ArrayDimensions=UInt32 Array[0]
AccessLevel=Readable
UserAccessLevel=Readable
MinimumSamplingInterval=50
Historizing=false

Hopefully these information are helpful.

Best regards!
Carsten

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Re: Subscribtion to server items

Post by Support Team »

Hello Carsten,

this looks strange because everything else works fine, it is just the Read (and the Subscription) that does not work.
Description: BadInvalidArgument(0x80ab0000)
the above error is normally not a big problem because the "description" is an attribute that is most likely empty anyway.

However, the "value" is missing, and that means the "Read" does not function
Value
SourceTimestamp=01.01.1601 01:00:00.000
SourcePicoseconds=0
ServerTimestamp=04.07.2014 10:12:15.621
ServerPicoseconds=0
StatusCode=Bad(0x80000000)
Value=Null
As all the rest works fine, this might be a problem when decoding SOAP messages. The XML parsers are all slightly different, and this might cause the problem. We have tested our parser against the OPC Foundation Reference XML-Server and it works great.
DataType = BaseDataType
The XML-DA Server seems to deliver incorrect (empty) data type of the particular value. This could also cause the described problems.

The next analytic step would be to record a wireshark between the UaGateway and the underlying XML-DA Server. In the capture file we should be able to see what is really the content of the SOAP-XML message. It seems to be some malformed XML content, that we canot parse.

What XML-DA Server are you using, is that server available as a free demo download somewhere?
Was that XML-DA Server tested for compliance?

Please record the wireshark and send it to our support email address.

Best Regards
Support Team

CarstenW
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Re: Subscribtion to server items

Post by CarstenW »

Hello Support-Team,

I am sorry for the long latency, but there were some other projects.

The XML-DA server was implemented by another company which is why there is regretly no demo server for download
and debugging. I don't have any information about the specification or compliance tests. But those servers are used in
productive environments for some years now without any issues.

I played around a bit with the following results.

1: There is still the problem described in the last post.

2: UaExpert can subscribe to the items and gets correct updates. The attribute monitor is still red because of the
already described erros.

3: UaExpert seems to be the only client, which can subscribe. Other clients can't subscribe correctly. The fail with
"BadAttributeIdInvalid Id: BadAttributeIdInvalid"

How can I send you the network dump without a customer ID?

Best regards
Carsten

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Re: Subscribtion to server items

Post by Support Team »

Hello,

you can send it by email.

Best regards
Support Team

CarstenW
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Re: Subscribtion to server items

Post by CarstenW »

Hello,

you can send it by email.

Best regards
Support Team
Hello,

on your email support page is written:
Please use this e-mail form to request support only if you have a valid support package. E-mails without valid customer information will not be processed.
That's the reason of my previous question about how to send without a customer ID.

Best regards
Carsten

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Re: Subscribtion to server items

Post by Support Team »

Just send an email without the customer ID.

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Re: Subscribtion to server items

Post by Support Team »

Carsten,

the analytics are pretty clear. The underlying XML DA Server is not giving a correct DataType fo the value. The Attribute Window of UaExpert is reading all attributes of the selected Item, unfortunately the DataType attribute is "empty".

When subscribing to the Item the UaExpert does not really care about the DataType (it is not explicitely reading it). The UaExpers just takes the "value" (no matter which DataType it has) and simply displays it.

So the Subscription may work correctly, but the Read on the Datatype attribute doesn't.
Anyway we can't see a problem in the UaGateway and neither in the UaExpert.

Best Regards
Support Team

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