Unable to browse tags using Siemens WinCC v 15

Hello, I have a Siemens S7300 that i would like to access the tags thru Ignition - Read and Write.

The tags are coming thru WinCC. i am able to connect to the OPC UA with the hostname and port, able to see all the system tags coming from WinCC, but no other tags.

I use v 7.9.12 of Ignition. Please help!

Were you able to solve this?

I have a similar error, trying to get tags from 1500 PLC with tags going through Wincc. I’m able to browse tags from UaExpert, but not from Ignition.

If you can get some screenshots of browsing from UaExpert, particularly the References pane, or a Wireshark capture, we might be able to figure out why.

Sure, this is the configuration from UAExpert, pretty standard:

Probably unrelated but worth mentioning: Upon the first connection, I get this warning, even after selecting None as security policy. I don’t have quarantined certificates in Ignition.

These are the references panels for both variable and server:
image image

And this is what I have in Igntiion (blank Tags folder). The “server” folder has tags.

I’ll work on a wireshark capture and send you in private.


Can you show me the references UaExpert sees from WinCC for the Tags folder? And perhaps the attributes panel for one of those “Bild” tags showing its attributes?

If this is a WinCC Panel with V15 firmware this is a known problem with Ignition. I think I sent you a wireshark recording some time ago.

UaException: status=Bad_ReferenceTypeIdInvalid, message=The operation could not be processed because all continuation points have been allocated.
	at com.inductiveautomation.ignition.gateway.opcua.client.connection.DataTypeTree$Companion.browse(DataTypeTree.kt:266)
	at com.inductiveautomation.ignition.gateway.opcua.client.connection.DataTypeTree$Companion$browse$1.invokeSuspend(DataTypeTree.kt)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
	at kotlinx.coroutines.DispatchedTask.run(Dispatched.kt:241)
	at kotlinx.coroutines.scheduling.CoroutineScheduler.runSafely(CoroutineScheduler.kt:594)
	at kotlinx.coroutines.scheduling.CoroutineScheduler.access$runSafely(CoroutineScheduler.kt:60)
	at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run(CoroutineScheduler.kt:740)

8.0.4 (b2019091612)
Azul Systems, Inc. 11.0.4

Huh, not ringing any bells, and the combination of StatusCode and error message there doesn’t make any sense :confused:

Nevermind, I found the PM from you @chi, but it was definitely a bug with this server.

It would be worth trying a current version of Ignition 8 just in case. I think the browse logic that’s happening here was updated to handle even a nonsense failure on the server’s part like this.

@eduardogarcia after looking at your Wireshark you may need to set the Max Per Operation advanced setting on the connection to something very low, like 50 or 100 to start, and try again. It seems the server is not exposing the nodes that indicate its operation limits.

Ok Good news, that fixed the browsing issue. Bad news when I try to subscribe to a tag, I get “uncertain initial value” and these errors:

Another Wireshark capture would probably help here.

Are you subscribing to all of the tags? Some? Are there certain tags that work and then when you add them it breaks?

Subscribing to only one tag, I’ve tried different datatypes and they all fail.

Here is the wireshark capture

wireSharkSubscriptionIssue.zip (12.0 KB)

Well, it’s complicated, but again this is a bug in this server. It’s indicating that the ByteString containing the encoded DataChangeNotification is null (length -1, FF FF FF FF in the following screenshot), which causes our decoder to move onto the next field and start decoding bogus data because the ByteString is actually present in the stream. Wireshark can see it because the way it’s written it ignores this length for built-in OPC UA types.

You’ll have to contact Siemens and see if they have a fix or upgrade available.

Thanks, will check if there’s a firmware update.