# OPC UA Connection to S7-1500 PLC Keeps Faulting **URL:** \ **Category:** Ignition\ **Tags:** opcua, ignition81, vision\ **Created:** [May 21, 2025, 6:40pm UTC](https://forum.inductiveautomation.com/t/opc-ua-connection-to-s7-1500-plc-keeps-faulting/106522 "2025-05-21T18:40:04Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![Jessy\_Underhill](https://avatars.discourse-cdn.com/v4/letter/j/90db22/32.png) [@Jessy\_Underhill](https://forum.inductiveautomation.com/u/Jessy_Underhill)\ **Post date:** [May 21, 2025, 6:40pm UTC](https://forum.inductiveautomation.com/t/opc-ua-connection-to-s7-1500-plc-keeps-faulting/106522/1 "2025-05-21T18:40:04Z")
I am getting the below error on my S7-1500 PLC OPC UA Server. Another thing of note is that the vision application and tag updates seem to be more sluggish than I'm familiar with. java.lang.Exception: session inactive: id=NodeId{ns=1, id=1326793202} name=ignition[Ignition-5044]\_SIMATIC.S7-1500.OPC-UA.Application:5044PLCA\_1747849305404 at com.inductiveautomation.ignition.gateway.opcua.client.connection.OpcUaConnection$MiloSessionActivityListener.onSessionInactive(OpcUaConnection.kt:499) at org.eclipse.milo.opcua.sdk.client.session.SessionFsmFactory.lambda$null$39(SessionFsmFactory.java:611) at java.base/java.util.concurrent.CopyOnWriteArrayList.forEach(Unknown Source) at org.eclipse.milo.opcua.sdk.client.session.SessionFsmFactory.lambda$configureActiveState$40(SessionFsmFactory.java:611) at com.digitalpetri.strictmachine.dsl.ActionBuilder$PredicatedTransitionAction.execute(ActionBuilder.java:119) at com.digitalpetri.strictmachine.StrictMachine$PollAndEvaluate.lambda$run$0(StrictMachine.java:242) at java.base/java.util.ArrayList.forEach(Unknown Source) at com.digitalpetri.strictmachine.StrictMachine$PollAndEvaluate.run(StrictMachine.java:227) at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.base/java.lang.Thread.run(Unknown Source) 8.1.39 (b2024040909) Azul Systems, Inc. 17.0.10 ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [May 21, 2025, 6:57pm UTC](https://forum.inductiveautomation.com/t/opc-ua-connection-to-s7-1500-plc-keeps-faulting/106522/2 "2025-05-21T18:57:44Z")
There may be some additional information in the logs. This stack trace you end up with on the status page isn't particularly useful - it's telling us we lost our session but not why we lost it. ---
**Author:** ![Jessy\_Underhill](https://avatars.discourse-cdn.com/v4/letter/j/90db22/32.png) [@Jessy\_Underhill](https://forum.inductiveautomation.com/u/Jessy_Underhill)\ **Post date:** [May 22, 2025, 11:52am UTC](https://forum.inductiveautomation.com/t/opc-ua-connection-to-s7-1500-plc-keeps-faulting/106522/3 "2025-05-22T11:52:20Z")
Well, that's helpful. (sarcasm) Thanks for responding, though. What area of the gateway would I find the logs related to this issue? (might be a dumb question once I know the answer) ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [May 22, 2025, 12:06pm UTC](https://forum.inductiveautomation.com/t/opc-ua-connection-to-s7-1500-plc-keeps-faulting/106522/4 "2025-05-22T12:06:32Z")
In the rest of the logs on the logs page, hopefully. > **[Diagnostics - Logs | Ignition User Manual](https://docs.inductiveautomation.com/docs/8.1/platform/gateway/status/diagnostics-logs)** > > One of the most important troubleshooting tools of the Gateway Webpage is the Logs page. This console shows errors caused by Gateway events including things like Database or Device connections, Authentication profiles, Alarm Journals and Pipelines,... This is probably something basic like the keep alive check between the client/server failing or somebody downloading to the PLC, which causes all Clients to lose connection and reconnect. ---
**Author:** ![Jessy\_Underhill](https://avatars.discourse-cdn.com/v4/letter/j/90db22/32.png) [@Jessy\_Underhill](https://forum.inductiveautomation.com/u/Jessy_Underhill)\ **Post date:** [May 22, 2025, 12:19pm UTC](https://forum.inductiveautomation.com/t/opc-ua-connection-to-s7-1500-plc-keeps-faulting/106522/5 "2025-05-22T12:19:43Z")
Yeah, I am very familiar with the OPC UA server dropping when I download to the PLC in TIA Portal. It normally doesn't seem to coincide with me doing that, but it could be that. I'll have to see if it's stable over the next few days, as I won't be making any PLC changes during that time. Thanks for helping me out, though; it's much appreciated.