# OPC UA server crash pfc200 **URL:** \ **Category:** CODESYS\ **Tags:** pfc200, codesys\ **Created:** [March 18, 2026, 6:54am UTC](https://www.wago.community/t/opc-ua-server-crash-pfc200/2638 "2026-03-18T06:54:56Z")\ **Posts on this page:** 14\ **Page:** 1
**Author:** ![\_sbohata](https://avatars.discourse-cdn.com/v4/letter/_/278dde/32.png) [@\_sbohata](https://www.wago.community/u/_sbohata)\ **Post date:** [March 18, 2026, 6:54am UTC](https://www.wago.community/t/opc-ua-server-crash-pfc200/2638/1 "2026-03-18T06:54:56Z")
Hello everyone! I’m having an issue where an unhandled exception in the OPC UA server causes the PLC to crash up to several times a day. The appearance of this exception is very inconsistent but from what I can tell it probably has something to do with an unstable network between the PLC and the client. Any kind of help or input on this issue is greatly appreciated. I attached the log file below. ![6b8df2ee-a11e-4c77-ad20-3ef957e61cc7](https://us1.discourse-cdn.com/flex016/uploads/wago/original/2X/b/b733d2521ead97b81aa48ab9dee43900582661c4.png) ---
**Author:** ![quenorha](https://sea2.discourse-cdn.com/flex016/user_avatar/www.wago.community/quenorha/32/429_2.png) [@quenorha](https://www.wago.community/u/quenorha)\ **Post date:** [March 18, 2026, 7:07am UTC](https://www.wago.community/t/opc-ua-server-crash-pfc200/2638/2 "2026-03-18T07:07:54Z")
Which firmware version are you running ? ---
**Author:** ![\_sbohata](https://avatars.discourse-cdn.com/v4/letter/_/278dde/32.png) [@\_sbohata](https://www.wago.community/u/_sbohata)\ **Post date:** [March 18, 2026, 7:21am UTC](https://www.wago.community/t/opc-ua-server-crash-pfc200/2638/3 "2026-03-18T07:21:26Z")
I’m using firmware 30 ---
**Author:** ![quenorha](https://sea2.discourse-cdn.com/flex016/user_avatar/www.wago.community/quenorha/32/429_2.png) [@quenorha](https://www.wago.community/u/quenorha)\ **Post date:** [March 18, 2026, 7:24am UTC](https://www.wago.community/t/opc-ua-server-crash-pfc200/2638/4 "2026-03-18T07:24:59Z")
Not sure if it will fix your issue but here is a FW30 patch 2 which fixes several bugs related to OPC UA ![image](https://us1.discourse-cdn.com/flex016/uploads/wago/original/2X/f/f4798f963329528065b162293127b8861bea660b.png) You can find it on the Download center ---
**Author:** ![\_sbohata](https://avatars.discourse-cdn.com/v4/letter/_/278dde/32.png) [@\_sbohata](https://www.wago.community/u/_sbohata)\ **Post date:** [March 18, 2026, 12:28pm UTC](https://www.wago.community/t/opc-ua-server-crash-pfc200/2638/5 "2026-03-18T12:28:06Z")
Thank you for the quick reply! I will try this new firmware as soon as I get the chance. By looking at the other logs from the PLC I can see similar error messages. I will reply back with results once I’m able to make the update. ---
**Author:** ![ALAIN\_DAUWE](https://avatars.discourse-cdn.com/v4/letter/a/ebca7d/32.png) [@ALAIN\_DAUWE](https://www.wago.community/u/ALAIN_DAUWE)\ **Post date:** [March 19, 2026, 5:51pm UTC](https://www.wago.community/t/opc-ua-server-crash-pfc200/2638/6 "2026-03-19T17:51:51Z")
I’ve had the same issues. I had over 35 tags to exchange, and every time the PLC crashes after a while. I moved the communication to Modbus TCP, and now it has been running for months without any further crashes. ---
**Author:** ![\_sbohata](https://avatars.discourse-cdn.com/v4/letter/_/278dde/32.png) [@\_sbohata](https://www.wago.community/u/_sbohata)\ **Post date:** [April 8, 2026, 5:13am UTC](https://www.wago.community/t/opc-ua-server-crash-pfc200/2638/7 "2026-04-08T05:13:25Z")
Hello! Unfortunately the firmware update made no difference and the error still occurs just like before. ---
**Author:** ![bertrand](https://avatars.discourse-cdn.com/v4/letter/b/a88e4f/32.png) [@bertrand](https://www.wago.community/u/bertrand)\ **Post date:** [April 22, 2026, 4:38pm UTC](https://www.wago.community/t/opc-ua-server-crash-pfc200/2638/8 "2026-04-22T16:38:13Z")
Hello, I’m experiencing the same crash issue. I’d be happy to share my experience with you. Thank you. Bertrand ---
**Author:** ![ALAIN\_DAUWE](https://avatars.discourse-cdn.com/v4/letter/a/ebca7d/32.png) [@ALAIN\_DAUWE](https://www.wago.community/u/ALAIN_DAUWE)\ **Post date:** [April 22, 2026, 5:57pm UTC](https://www.wago.community/t/opc-ua-server-crash-pfc200/2638/9 "2026-04-22T17:57:26Z")
Hello, The OPC server was not due to handle multiple tags. Since I migrated to Modbus, my problem has been resolved. I currently have 126 tags with Modbus, with no issues. ---
**Author:** ![TomasD](https://sea2.discourse-cdn.com/flex016/user_avatar/www.wago.community/tomasd/32/2042_2.png) [@TomasD](https://www.wago.community/u/TomasD)\ **Post date:** [April 23, 2026, 3:19pm UTC](https://www.wago.community/t/opc-ua-server-crash-pfc200/2638/10 "2026-04-23T15:19:54Z")
How many tags do you have? I have 8212 with FW30 no problems. OPC UA works with approximately 60 tags. ---
**Author:** ![\_sbohata](https://avatars.discourse-cdn.com/v4/letter/_/278dde/32.png) [@\_sbohata](https://www.wago.community/u/_sbohata)\ **Post date:** [April 23, 2026, 4:30pm UTC](https://www.wago.community/t/opc-ua-server-crash-pfc200/2638/11 "2026-04-23T16:30:27Z")
I’m using a 8212 as well but with around 800 tags. I have been told that OPC UA works perfectly for other people using thousands of tags though so I’m not sure the issue is with the tag count. ---
**Author:** ![\_sbohata](https://avatars.discourse-cdn.com/v4/letter/_/278dde/32.png) [@\_sbohata](https://www.wago.community/u/_sbohata)\ **Post date:** [June 22, 2026, 1:19pm UTC](https://www.wago.community/t/opc-ua-server-crash-pfc200/2638/12 "2026-06-22T13:19:15Z")
Hello, I’ve had great success in terms of stability with the following configuration under /etc/codesys3.d/CODESYSControl\_User.cfg. [CmpOPCUAServer] MaxSessions=32 SessionTimeout=60000 SchedulerResolution=20 ItemMinSamplingRate=500 WorkerTaskDynamic=0 WorkerTasksMax=20 MaxQueueSize=100 Priority=50 [CmpOPCUAStack] TraceLevel=1023 MaxBufferSize=16777216 MaxMessageSize=2097152 Ever since I set these parameters I have experienced no crashes on the PLC. From my experience a stable network connection is also required. Make sure that your network has no packet loss and there’s enough bandwidth to support the OPC UA server communication. ---
**Author:** ![hkn\_blt](https://avatars.discourse-cdn.com/v4/letter/h/9f8e36/32.png) [@hkn\_blt](https://www.wago.community/u/hkn_blt)\ **Post date:** [June 22, 2026, 1:56pm UTC](https://www.wago.community/t/opc-ua-server-crash-pfc200/2638/13 "2026-06-22T13:56:19Z")
> [@\_sbohata](#): > > /etc/codesys3.d/CODESYSControl\_User.cfg Did you add these commands to this file? Or did you modify the existing ones? ---
**Author:** ![\_sbohata](https://avatars.discourse-cdn.com/v4/letter/_/278dde/32.png) [@\_sbohata](https://www.wago.community/u/_sbohata)\ **Post date:** [June 23, 2026, 4:42am UTC](https://www.wago.community/t/opc-ua-server-crash-pfc200/2638/14 "2026-06-23T04:42:04Z")
I added these lines to CODESYSControl\_User.cfg. I don’t think any of them are in it by default.