Using OPC UA Server by 3rd party


I want to use “ignition opc ua server” in an external application (no inductive technology). Now this ua server is collecting data using Siemens Driver.

I want to read some Siemens data from this OPC.

I am be able to connect with OPC Server even read some internal tags.

But when I try to read tags from Siemens, the result is wrong.

I don´t know if I´m addressing tags incorrectly.

For example, I have a simultation device called “Simulacion 1” and I can read some tags with the following syntax :smiley:evices.[Simulacion 1].Refrigeration.accumulatorLevel

The Real PLC I wanna read tags is called “paletizador”. If a trying to read a paletizador´s system tag the result is right with the following syntax: Devices.[paletizador].[Diagnostics].Requests.Last Duration

I am trying to read the address DB201.DB2, so the sintax would be as follows (I think): Devices.[paletizador]DB201,B2. But I don´t recieve any update data.

I don´t find information about the OPC Path and it doesn´t support auto-browsing for siemens driver

Could anybody help me?


I don’t know what format your paths are in, but I suspect the comma might be throwing it off somehow.

What you need to do is read or subscribe to a node with the NodeId ns=1:s=DB201,B2 or in other words a NodeId in namespace 1, with a string identifier equal to “DB201,B2”.

How you accomplish that in your client software is something you’ll have to figure out, but you need to make sure whatever your paths are resolve to the correct NodeIds.

Hi Kevin,

I think my problem could be the comma.

I´ve figured out how to read from muy client to OPC UA Server by browsing. But when I get my Plc level, browsing is not supported.

I´ve try various combinations (with comma, with dot, etc) and always the result was wrong.

At least, I want to confirm if the addressing in my case (DB201,B2) is correct (apart from the comma).

I want to check if anybody has had the same situation as me



your address DB201,B2 is correct, but i think your node id is wrong. The node id is not the address you see while browsing tags. The node id of your diagnostic is e.g.

NS1|String|[paletizador]_Meta:[Diagnostics]/Requests/Last Duration

so your DB byte will have the node id


The above node id format works with the client that i’m using (Unified Automation), maybe your client uses another syntax for namespace and String format.


Hi chi,

It seems each OPC client use diferent syntax to make the path. In my app the diagnostic tag is Devices.[paletizador].[Diagnostics].Requests.Last Duration.

Previous my app, I use UA Expert software to check the tagpath from an external client (not inside of ignition) and the result paths was as you said.

But if the syntax DB201,B2 is an advance.