# OPC connection issues with FANUC FASOPC

**URL:** <https://forum.inductiveautomation.com/t/opc-connection-issues-with-fanuc-fasopc/104404>\
**Category:** Ignition\
**Created:** [March 28, 2025, 8:54pm UTC](https://forum.inductiveautomation.com/t/opc-connection-issues-with-fanuc-fasopc/104404 "2025-03-28T20:54:02Z")\
**Posts on this page:** 15\
**Page:** 1

<div class="post-metadata">

**Author:** ![Simon\_Hathout\_Willar](https://avatars.discourse-cdn.com/v4/letter/s/3da27b/32.png) [@Simon\_Hathout\_Willar](https://forum.inductiveautomation.com/u/Simon_Hathout_Willar)\
**Post date:** [March 28, 2025, 8:54pm UTC](https://forum.inductiveautomation.com/t/opc-connection-issues-with-fanuc-fasopc/104404/1 "2025-03-28T20:54:02Z")

</div>

Hello.

We have a large number of Fanuc CNC's, and use FASOPC to connect to these machines. We have a server running FASOPC as a service (this also is the same server which runs Ignition and SQL Server, there is not enough traffic yet to require splitting these onto separate machines).

We've been noticing that the tags we pull from FASOPC will all go to dataintegrity = 600 (in the historian, this maps to unknown quality) -- the live tags also go to unknown quality. This happens across all machines simultaneously, so it's not an issue with the connection to one machine. It happens roughly once a day, though not at a prescribed time.

FASOPC does not "notice" that it isn't running, and doesn't take automatic action to reset. It also does not record anything related to losing connectivity in its log files.

Ignition also does not notice anything strange happen. The gateway logs don't have any data related to the OPC connection.

Restarting the FASOPC service brings it back online. Right now, we have a somewhat hacky script running, which polls each machine every 5 minutes for connectivity, and if none of them respond, runs a batch file on the server which restarts FASOPC. This is not a good long term solution.

As a detailed timeline from last night:

- At 11:33:30, the historian records all the live tags as going to dataintegrity = 600. A script which calls system.opc.getServerState on this change records "FAULTED"
- At 11:35:01, the manual script detects the connectivity issues, and restarts the FASOPC server
- At 11:35:16, the OpcUAConncetion logger records "Subscription watchdog timer elapsed", as well as "Subscription transfer failed". (This is due to the FASOPC server being now turned off).
- After 11:35:22, historian logs all tags as going back to dataintegrity = 192 (good).

Does anyone have any advice to troubleshoot this? Eg, is there a way to collect even more detailed logs on the OPC connection

---

<div class="post-metadata">

**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:** [March 28, 2025, 9:05pm UTC](https://forum.inductiveautomation.com/t/opc-connection-issues-with-fanuc-fasopc/104404/2 "2025-03-28T21:05:34Z")

</div>

The loggers you find searching for these terms, set to DEBUG level may help:

- OpcUaConnection
- OpcUaSubscriptionModel
- OpcUaSubscriptionSynchronizer

along with a Wireshark capture if you can disable security for the connection(s).

That said... this message:

> [@Simon\_Hathout\_Willar](#):
>
> At 11:35:16, the OpcUAConncetion logger records "Subscription watchdog timer elapsed", as well as "Subscription transfer failed". (This is due to the FASOPC server being now turned off).

is already telling me this server has basically stopped responding - that's watchdog timer's job, to detect if we stopped getting even the keep alive notifications for a subscription.

Ignition will try to recover by creating the subscriptions again, etc... but if the server has failed its way into a state where it needs a restart there's nothing you can do from Ignition.

You'll need to upload full log exports now and in the future for more help.

---

<div class="post-metadata">

**Author:** ![Simon\_Hathout\_Willar](https://avatars.discourse-cdn.com/v4/letter/s/3da27b/32.png) [@Simon\_Hathout\_Willar](https://forum.inductiveautomation.com/u/Simon_Hathout_Willar)\
**Post date:** [March 28, 2025, 9:23pm UTC](https://forum.inductiveautomation.com/t/opc-connection-issues-with-fanuc-fasopc/104404/3 "2025-03-28T21:23:54Z")

</div>

> [@Kevin.Herron](#):
>
> is already telling me this server has basically stopped responding

Sorry, I don't think I was clear enough on that note. I know why it is turned off, that is because we manually killed the FASOPC server using an external script. I am not sure if a restart is required to get the server responding again, only that it is sufficient to do so.

It stopped responding at 11:33:30. Our script detected this at 11:35, and told the FASOPC server to restart. Only after we told the server to restart, did we get the watchdog timer error.

> [@Kevin.Herron](#):
>
> You'll need to upload full log exports now and in the future for more help.

Are there any dangers to uploading log files to a public forum? And any way to limit the log files to a specific period of time? (those I downloaded from the gateway seem to be for the past 2 months)

---

<div class="post-metadata">

**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:** [March 28, 2025, 9:25pm UTC](https://forum.inductiveautomation.com/t/opc-connection-issues-with-fanuc-fasopc/104404/4 "2025-03-28T21:25:26Z")

</div>

> [@Simon\_Hathout\_Willar](#):
>
> Are there any dangers to uploading log files to a public forum?

Only if you're printing out information you think is proprietary for some reason. In that case you'll have to work with support.

Otherwise, no, there's not any kinds of passwords or things like that in the logs.

---

<div class="post-metadata">

**Author:** ![Simon\_Hathout\_Willar](https://avatars.discourse-cdn.com/v4/letter/s/3da27b/32.png) [@Simon\_Hathout\_Willar](https://forum.inductiveautomation.com/u/Simon_Hathout_Willar)\
**Post date:** [March 28, 2025, 9:33pm UTC](https://forum.inductiveautomation.com/t/opc-connection-issues-with-fanuc-fasopc/104404/5 "2025-03-28T21:33:07Z")

</div>

Alright. I've attached the logs for the hour where we had issues. You can safely ignore the tag change script errors, those are from the script I set up to check the status of the connection.

(I used Kindling to get a text version of the logs, for just the period of time in question)

[logs.txt](https://forum.inductiveautomation.com/uploads/short-url/hxXgwA00qEFAVXaylLG2Q9u4b5U.txt) (11.8 KB)

---

<div class="post-metadata">

**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:** [March 28, 2025, 9:35pm UTC](https://forum.inductiveautomation.com/t/opc-connection-issues-with-fanuc-fasopc/104404/6 "2025-03-28T21:35:11Z")

</div>

The only thing remotely relevant in there is:

```python
2025-03-27 23:35:16:594 opc-ua-executor-13837
Subscription watchdog timer elapsed, id=946580724

2025-03-27 23:35:21:558 opc-ua-executor-13840
Subscription transfer failed, id=946580724, status=StatusCode{name=Bad_SubscriptionIdInvalid, value=0x80280000, quality=bad}

2025-03-27 23:35:21:695 opc-ua-executor-13841
ResendData for subscriptionId=2392543966 succeeded.

```

Hopefully you get some more usable info with those loggers on.

---

<div class="post-metadata">

**Author:** ![Simon\_Hathout\_Willar](https://avatars.discourse-cdn.com/v4/letter/s/3da27b/32.png) [@Simon\_Hathout\_Willar](https://forum.inductiveautomation.com/u/Simon_Hathout_Willar)\
**Post date:** [March 28, 2025, 9:36pm UTC](https://forum.inductiveautomation.com/t/opc-connection-issues-with-fanuc-fasopc/104404/7 "2025-03-28T21:36:22Z")

</div>

Yep, but I already know the cause of those.

I'll set the additional loggers to debug, and hopefully capture something over the weekend.

Cheers.

---

<div class="post-metadata">

**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:** [March 28, 2025, 9:47pm UTC](https://forum.inductiveautomation.com/t/opc-connection-issues-with-fanuc-fasopc/104404/8 "2025-03-28T21:47:04Z")

</div>

For reference, what version of Ignition is this?

---

<div class="post-metadata">

**Author:** ![Simon\_Hathout\_Willar](https://avatars.discourse-cdn.com/v4/letter/s/3da27b/32.png) [@Simon\_Hathout\_Willar](https://forum.inductiveautomation.com/u/Simon_Hathout_Willar)\
**Post date:** [March 28, 2025, 10:14pm UTC](https://forum.inductiveautomation.com/t/opc-connection-issues-with-fanuc-fasopc/104404/9 "2025-03-28T22:14:46Z")

</div>

Ignition Platform`8.1.38`  
OPC-UA Module `9.1.38`

---

<div class="post-metadata">

**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:** [March 28, 2025, 10:16pm UTC](https://forum.inductiveautomation.com/t/opc-connection-issues-with-fanuc-fasopc/104404/10 "2025-03-28T22:16:27Z")

</div>

Ok thanks. Was hoping it was earlier than that; found a ticket that might have been relevant, but it was released as part of 8.1.38.

---

<div class="post-metadata">

**Author:** ![Simon\_Hathout\_Willar](https://avatars.discourse-cdn.com/v4/letter/s/3da27b/32.png) [@Simon\_Hathout\_Willar](https://forum.inductiveautomation.com/u/Simon_Hathout_Willar)\
**Post date:** [April 8, 2025, 7:25pm UTC](https://forum.inductiveautomation.com/t/opc-connection-issues-with-fanuc-fasopc/104404/11 "2025-04-08T19:25:38Z")

</div>

I ran the loggers, however they don't seem to have anything more obvious.  
For this event, my tag quality went to poor at 15:10:39, and recovered at 15:15:20.

The automatic shutdown/start back up of the FASOPC server seems to have happened at 15:15 (I'll add some logging to this script, so I can get a more accurate time estimate)

> **The relevant logs**
>
> 2025-04-03 15:10:39:740 opc-ua-executor-16638  
> handleStoreLastKnownQualities()
> 
> 2025-04-03 15:12:25:661 opc-ua-executor-16638  
> handleRemoveSubscription(subscriptionId=1466220523)
> 
> 2025-04-03 15:12:25:661 opc-ua-executor-16640  
> Subscription watchdog timer elapsed, id=1466220523
> 
> 2025-04-03 15:12:25:662 opc-ua-executor-16638  
> Removed subscription; id=1466220523, name=tag-group-default\_default
> 
> 2025-04-03 15:12:25:662 opc-ua-executor-16640  
> debounce: synchronize received
> 
> 2025-04-03 15:12:25:913 opc-ua-executor-16638  
> debounce: synchronize sent
> 
> 2025-04-03 15:12:25:913 opc-ua-executor-16632  
> handleSynchronize()
> 
> 2025-04-03 15:12:25:913 opc-ua-executor-16632  
> Creating subscription 'tag-group-default\_default' @ publishingInterval=500.0ms
> 
> 2025-04-03 15:12:39:512 opc-ua-executor-16640  
> synchronizeSubscriptions() took 13599ms
> 
> 2025-04-03 15:12:39:512 opc-ua-executor-16640  
> synchronizeMonitoredItems() took 0ms
> 
> 2025-04-03 15:12:39:512 opc-ua-executor-16640  
> synchronizeSettings() took 0ms
> 
> 2025-04-03 15:12:39:512 opc-ua-executor-16640  
> synchronized=false; next re-synchronization in 8 seconds
> 
> 2025-04-03 15:12:39:512 opc-ua-executor-16640  
> Failed to create subscription 'tag-group-default\_default': timed out waiting for acknowledge
> 
> 2025-04-03 15:12:39:512 opc-ua-executor-16640  
> subscriptionName=tag-group-default\_default, ignSubscription=com.inductiveautomation.ignition.gateway.opcua.client.connection.OpcUaSubscriptionModel$IgnitionSubscription@537daef, opcSubscription=null
> 
> 2025-04-03 15:12:47:514 opc-ua-executor-16638  
> handleResynchronize()
> 
> 2025-04-03 15:12:47:514 opc-ua-executor-16640  
> debounce: synchronize received
> 
> 2025-04-03 15:12:47:766 opc-ua-executor-16640  
> debounce: synchronize sent
> 
> 2025-04-03 15:12:47:766 opc-ua-executor-16638  
> handleSynchronize()
> 
> 2025-04-03 15:12:47:766 opc-ua-executor-16638  
> Creating subscription 'tag-group-default\_default' @ publishingInterval=500.0ms
> 
> 2025-04-03 15:13:00:611 opc-ua-executor-16632  
> synchronizeSubscriptions() took 12845ms
> 
> 2025-04-03 15:13:00:611 opc-ua-executor-16632  
> synchronizeMonitoredItems() took 0ms
> 
> 2025-04-03 15:13:00:611 opc-ua-executor-16632  
> synchronizeSettings() took 0ms
> 
> 2025-04-03 15:13:00:611 opc-ua-executor-16632  
> synchronized=false; next re-synchronization in 16 seconds
> 
> 2025-04-03 15:13:00:611 opc-ua-executor-16632  
> Failed to create subscription 'tag-group-default\_default': timed out waiting for acknowledge
> 
> 2025-04-03 15:13:00:611 opc-ua-executor-16632  
> subscriptionName=tag-group-default\_default, ignSubscription=com.inductiveautomation.ignition.gateway.opcua.client.connection.OpcUaSubscriptionModel$IgnitionSubscription@537daef, opcSubscription=null
> 
> 2025-04-03 15:13:16:611 opc-ua-executor-16640  
> handleResynchronize()
> 
> 2025-04-03 15:13:16:611 opc-ua-executor-16638  
> debounce: synchronize received
> 
> 2025-04-03 15:13:16:862 opc-ua-executor-16638  
> debounce: synchronize sent
> 
> 2025-04-03 15:13:16:862 opc-ua-executor-16632  
> handleSynchronize()
> 
> 2025-04-03 15:13:16:862 opc-ua-executor-16632  
> Creating subscription 'tag-group-default\_default' @ publishingInterval=500.0ms
> 
> 2025-04-03 15:13:21:712 opc-ua-executor-16632  
> synchronizeSubscriptions() took 4850ms
> 
> 2025-04-03 15:13:21:712 opc-ua-executor-16632  
> synchronizeMonitoredItems() took 0ms
> 
> 2025-04-03 15:13:21:712 opc-ua-executor-16632  
> synchronizeSettings() took 0ms
> 
> 2025-04-03 15:13:21:712 opc-ua-executor-16632  
> synchronized=false; next re-synchronization in 32 seconds
> 
> 2025-04-03 15:13:21:712 opc-ua-executor-16632  
> Failed to create subscription 'tag-group-default\_default': timed out waiting for acknowledge
> 
> 2025-04-03 15:13:21:712 opc-ua-executor-16632  
> subscriptionName=tag-group-default\_default, ignSubscription=com.inductiveautomation.ignition.gateway.opcua.client.connection.OpcUaSubscriptionModel$IgnitionSubscription@537daef, opcSubscription=null
> 
> 2025-04-03 15:13:53:712 opc-ua-executor-16641  
> handleResynchronize()
> 
> 2025-04-03 15:13:53:712 opc-ua-executor-16640  
> debounce: synchronize received
> 
> 2025-04-03 15:13:53:964 opc-ua-executor-16641  
> debounce: synchronize sent
> 
> 2025-04-03 15:13:53:964 opc-ua-executor-16640  
> handleSynchronize()
> 
> 2025-04-03 15:13:53:964 opc-ua-executor-16640  
> Creating subscription 'tag-group-default\_default' @ publishingInterval=500.0ms
> 
> 2025-04-03 15:14:03:912 opc-ua-executor-16640  
> synchronizeSubscriptions() took 9948ms
> 
> 2025-04-03 15:14:03:912 opc-ua-executor-16640  
> synchronizeMonitoredItems() took 0ms
> 
> 2025-04-03 15:14:03:912 opc-ua-executor-16640  
> synchronizeSettings() took 0ms
> 
> 2025-04-03 15:14:03:912 opc-ua-executor-16640  
> synchronized=false; next re-synchronization in 64 seconds
> 
> 2025-04-03 15:14:03:912 opc-ua-executor-16640  
> Failed to create subscription 'tag-group-default\_default': timed out waiting for acknowledge
> 
> 2025-04-03 15:14:03:912 opc-ua-executor-16640  
> subscriptionName=tag-group-default\_default, ignSubscription=com.inductiveautomation.ignition.gateway.opcua.client.connection.OpcUaSubscriptionModel$IgnitionSubscription@537daef, opcSubscription=null
> 
> 2025-04-03 15:15:07:914 opc-ua-executor-16640  
> handleResynchronize()
> 
> 2025-04-03 15:15:07:914 opc-ua-executor-16642  
> debounce: synchronize received
> 
> 2025-04-03 15:15:08:165 opc-ua-executor-16638  
> debounce: synchronize sent
> 
> 2025-04-03 15:15:08:165 opc-ua-executor-16640  
> handleSynchronize()
> 
> 2025-04-03 15:15:08:165 opc-ua-executor-16640  
> Creating subscription 'tag-group-default\_default' @ publishingInterval=500.0ms
> 
> 2025-04-03 15:15:20:122 opc-ua-executor-16638  
> Subscription transfer failed, id=1466220523, status=StatusCode{name=Bad\_SubscriptionIdInvalid, value=0x80280000, quality=bad}
> 
> 2025-04-03 15:15:20:224 opc-ua-executor-16632  
> synchronizeSubscriptions() took 12059ms
> 
> 2025-04-03 15:15:20:224 opc-ua-executor-16632  
> subscription=tag-group-default\_default calculating itemsToCreate and itemsToDelete took 0ms
> 
> 2025-04-03 15:15:20:224 opc-ua-executor-16632  
> subscription=tag-group-default\_default itemsToCreate.size()=911
> 
> 2025-04-03 15:15:20:225 opc-ua-executor-16632  
> subscription=tag-group-default\_default itemsToDelete.size()=0
> 
> 2025-04-03 15:15:20:226 opc-ua-executor-16632  
> Creating 911 items on subscription 'tag-group-default\_default'...
> 
> 2025-04-03 15:15:20:257 opc-ua-executor-16632  
> synchronizeMonitoredItems() took 33ms
> 
> 2025-04-03 15:15:20:257 opc-ua-executor-16632  
> Setting MonitoringMode.Reporting on 911 items on subscription 'tag-group-default\_default'...
> 
> 2025-04-03 15:15:20:258 opc-ua-executor-16632  
> synchronizeSettings() took 1ms
> 
> 2025-04-03 15:15:20:258 opc-ua-executor-16632  
> handleRemoveSubscription(subscriptionId=1466220523)
> 
> 2025-04-03 15:15:20:258 opc-ua-executor-16632  
> Calling ResendData for subscriptionId=3728193898
> 
> 2025-04-03 15:15:20:258 opc-ua-executor-16638  
> debounce: synchronize received
> 
> 2025-04-03 15:15:20:258 opc-ua-executor-16638  
> handleClearLastKnownQualities(subscriptionId=3728193898)
> 
> 2025-04-03 15:15:20:258 opc-ua-executor-16638  
> ResendData for subscriptionId=3728193898 succeeded.
> 
> 2025-04-03 15:15:20:510 opc-ua-executor-16638  
> debounce: synchronize sent
> 
> 2025-04-03 15:15:20:510 opc-ua-executor-16640  
> handleSynchronize()
> 
> 2025-04-03 15:15:20:510 opc-ua-executor-16640  
> synchronizeSubscriptions() took 0ms
> 
> 2025-04-03 15:15:20:510 opc-ua-executor-16640  
> subscription=tag-group-default\_default calculating itemsToCreate and itemsToDelete took 0ms
> 
> 2025-04-03 15:15:20:510 opc-ua-executor-16640  
> subscription=tag-group-default\_default itemsToCreate.size()=0
> 
> 2025-04-03 15:15:20:510 opc-ua-executor-16640  
> subscription=tag-group-default\_default itemsToDelete.size()=0
> 
> 2025-04-03 15:15:20:510 opc-ua-executor-16640  
> synchronizeMonitoredItems() took 0ms
> 
> 2025-04-03 15:15:20:510 opc-ua-executor-16640  
> synchronizeSettings() took 0ms

---

<div class="post-metadata">

**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:** [April 8, 2025, 7:36pm UTC](https://forum.inductiveautomation.com/t/opc-connection-issues-with-fanuc-fasopc/104404/12 "2025-04-08T19:36:27Z")

</div>

It looks like this server has just stopped responding at some point.

The opening log message there about storing last know qualities happens in response to an `onSessionInactive` callback, which happens either when we lost the connection or when the keep alive has failed enough times that we initiate a reconnect.

There's not much to do on the Ignition side besides maybe play with the keep alive settings to see if the server eventually recovers.

If you want objective proof to go to FANUC with then you'll have to work with support and provide unredacted logs and a Wireshark capture.

---

<div class="post-metadata">

**Author:** ![Simon\_Hathout\_Willar](https://avatars.discourse-cdn.com/v4/letter/s/3da27b/32.png) [@Simon\_Hathout\_Willar](https://forum.inductiveautomation.com/u/Simon_Hathout_Willar)\
**Post date:** [April 8, 2025, 7:42pm UTC](https://forum.inductiveautomation.com/t/opc-connection-issues-with-fanuc-fasopc/104404/13 "2025-04-08T19:42:30Z")

</div>

Sounds good.

I'd reached out to FANUC a few months ago, but they looked through the FASOPC logs, and weren't able to find anything interesting there either.

Looks like I'll need to bang my head into this problem a little more.

Thanks for the help.

---

<div class="post-metadata">

**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:** [April 8, 2025, 7:49pm UTC](https://forum.inductiveautomation.com/t/opc-connection-issues-with-fanuc-fasopc/104404/14 "2025-04-08T19:49:20Z")

</div>

That's the problem with logs, from either side.

Wireshark will tell you the truth 🙂

---

<div class="post-metadata">

**Author:** ![koenraad.lievens](https://avatars.discourse-cdn.com/v4/letter/k/9f8e36/32.png) [@koenraad.lievens](https://forum.inductiveautomation.com/u/koenraad.lievens)\
**Post date:** [April 15, 2026, 11:35am UTC](https://forum.inductiveautomation.com/t/opc-connection-issues-with-fanuc-fasopc/104404/15 "2026-04-15T11:35:21Z")

</div>

Where you able to find a solution? I seem to have the same problem.