UA server SourceNode returning multiple TargetNodes with the same NodeId|OPC UA Standard|Forum|OPC Foundation

Avatar
Search
Forum Scope


Match



Forum Options



Minimum search word length is 3 characters - maximum search word length is 84 characters
Lost password?
sp_Feed sp_PrintTopic sp_TopicIcon
UA server SourceNode returning multiple TargetNodes with the same NodeId
Avatar
Mark Rice
Member
Members
Forum Posts: 6
Member Since:
09/11/2015
sp_UserOfflineSmall Offline
1
06/21/2024 - 07:14
sp_Permalink sp_Print

I have a UA client that is browsing a server. When I get the TargetNodes from a particular SourceNode, it is returning 2 TargetNodes with the same NodeId. One is an Object and one is a Variable. Is this allowed? I cannot find anything in the spec that says one way or the other.

Avatar
Randy Armstrong
Admin
Forum Posts: 1578
Member Since:
05/30/2017
sp_UserOfflineSmall Offline
2
06/21/2024 - 21:36
sp_Permalink sp_Print

NodeIds identify one Node.

A Node may have many NodeIds

The NodeId Attribute always returns the canonical NodeId.

Sounds like this server is not compliant.

Avatar
Mark Rice
Member
Members
Forum Posts: 6
Member Since:
09/11/2015
sp_UserOfflineSmall Offline
3
06/24/2024 - 05:29
sp_Permalink sp_Print sp_EditHistory

Let me make sure I understand what you are saying. It is not legal to have the same NodeId more than one place in the address space. If the same “Node” exists in more than place in the address space, the references must point to the exact same node. If the node is an alias of some kind so it isn’t exactly the same, then it must have a different NodeId. In my customers case, they have a reference to a Node that has a Node class of Variable and a separate reference to a Node that has a Node class of Object, but both Nodes have the same NodeId and they both have the same child references. So that is a violation of the spec. Is this correct?

Let me try to be more specific. When we call browse for forward references on a particular NodeId, we get back 2 references. They both have the same BrowseName and the same NodeId. The difference is they have different NodeClasses. Based on the above discussion, I am thinking this is not allowed.

Avatar
Randy Armstrong
Admin
Forum Posts: 1578
Member Since:
05/30/2017
sp_UserOfflineSmall Offline
4
06/25/2024 - 09:50
sp_Permalink sp_Print sp_EditHistory

Yes that is not allowed. 2 different NodeClasses mean 2 different Nodes with the same NodeId.

What would happen if the ‘Value’ or ‘EventNotifier’ attribute is read?

It makes no sense. I suspect it is simply bug in the server where the NodeClass is set incorrectly

Forum Timezone: America/Phoenix
Most Users Ever Online: 510
Currently Online:
Guest(s) 25
Currently Browsing this Page:
1 Guest(s)
Top Posters:
Forum Stats:
Groups: 2
Forums: 10
Topics: 1444
Posts: 4887