UaGateway items name to OPC DA Client

[GBettini]

Hello Support,
I'm evaluating UaGateway because I need to connect a new system (OPC UA Server) to an old system (OPC DA Client).
The old system OPC DA client look for specific item names and in new system OPC UA Server I named the item as expected. Actually the problem is UaGateway, during tag browsing, expose item name as I wrote, but on item connection the name will change to NodeId. This not happen using a native OPC UA Client. There is any solution to enforce UaGateway to use specific name also during item connection?

I attach some screen shot to explain better what I mean. The new system OPC UA Server name is "TestopcServer1_IOServer" and I try to use different OPC client, both UA and DA by UaGateway, to connect it.

The new system tags are called AAA_BBB_CCC_01 and DDD_EEE_FFF_01
Image OPC_UA_UaExpert_Client.png : you can see tags as used from OPC UA UaExpert Client
Image OPC_UA_OpcFoundation_Client.png : you can see tags as used from OPC UA OpcFoundation Client
Image OPC_DA_Softing_Client_1.png : you can see tags as used from OPC DA Softing Client during tag browsing
Image OPC_DA_Softing_Client_2.png : you can see tags as used from OPC DA Softing Client after item connection
Image OPC_DA_Matrikon_Client_1.png : you can see tags as used from OPC DA Matrikon Client during tag browsing
Image OPC_DA_Matrikon_Client_2.png : you can see tags as used from OPC DA Matrikon Client after item connection

[Support Team]

Hi,

ItemName in COM DA and DisplayName/BrowseName in OPC UA are just for display purpose or used to identify a node at one browse position in the tree.

ItemId in COM DA and NodeId in OPC UA are the unique identifiers (fully qualified names) for a node and can be completely independent of the node name.

The COM DA Server of UaGateway can only use the NodeId of the underlying OPC UA server to create a unique ItemId. The OPC UA DisplayName or BrowseName cannot be used because they are not defined as unique across the whole address space.

The NodeId in OPC UA is a structure with an Identifier and a Namespace.. The identifier must be unique in the namespace. The server provides a table with the namespace URIs and the index into this table is used in the NodeId structure.

Since the UaGateway can aggregate several OPC UA servers, the namespace URI in the UaGateway is constructed from a prefix and the URI of the namespace in the underlying server. By default, the prefix is the ServerURI of the aggregated server since it must be unique for the server in the network. As alternative the name for the server in the UaGateway can be used (configuration option for the connection).

Since the COM DA ItemId is just a string, it is constructed from the Namespace URI of the NodeId in UaGateway and the Identifier part of the NodeId.

Since you are using GUID NodeIds in the server, the ItemID is a combination of <ServerUri of aggregated server>/<Namespace URI in aggregated server>|G|<GUID>.


But UaGateway has an option to create ItemIds which are identical to the string identifier of the underlying OPC UA Server.
If you
- have just one OPC UA server
- all nodes are in one namespace in this one OPC UA server
- use String Identifiers in the NodeId
- the string Identifier matches the name or the node
- the names are unique in the namespace

you can configure UaGateway to omit this one NamespaceURI in the ItemID.
See "Default Name Space" in UaGateway administration:
http://documentation.unified-automation ... da_general

Best Regards,
Unified Automation Support Team

[GBettini]

Hi,
thank you for your reply.
I made some test to try to avoid the namespace form items. I've used all entry in Default NameSpace list (see attached image) but without any success: in OPC DA client. items are always linked using the full name like "urn:localhost:Platform.NExT IOServer:TestOpcServer1_IOServer/http://progea.com/UFUAServer/ModelG|{49 ... 07c6d607aa}".
In your message you told me that "the string Identifier matches the name or the node" but, in my case, I have NodeId as GUID like {49463fa6-af4b-461f-b65a-d707c6d607aa} and DisplayName as string like "AAA_BBB_CCC_01". Due to some system limitation I cannot use the same string in both values. Is this absolutely necessary to avoid the namespace part?
Thanks for your help.
Best Regards

[Support Team]

Hi,

Omitting the namepace URI from the ItemID works only for String Identifiers.

Like mentioned above, the Name cannot be used as ItemID. Only the Identifier/NodeId can be used as ItemID.

Best Regards,
Unified Automation Support Team