Troubleshooting Intermittent Tag Update Problems

I have recently added a new device, a ControlLogix 1756-L72 5570 which is running on firmware 21.11, to an older Ignition project. The gateway is version 7.7.3.

The existing project is rather large, with nearly 90,000 tags all from only 2 controllers, another similar controllogix and a compactlogix 1769 L33ER. Both are running firmware 20.13. These tags are all on the same scanclass at 1000ms. That said, there have been no issues for the last few years.

I am having problems with the tags from the new controller freezing up periodically, watching a timer tag, I can see that it counts up for a few seconds, then hangs for a few seconds, and eventually updates or returns bad quality. This issue is unique to the new tags - the old tags on the same scan class are updating just fine simultaneously.

Some research on these forums suggests that it may be an issue with this earlier version of the Logix driver. The older PLCs running version 20 are using the ControlLogix and CompactLogix drivers, but I needed to use the generic Logix driver for the newer v21 controller.

Are there any troubleshooting steps that I can take to confirm this, or is there another likely culprit? The system console shows no relevant errors, and the status->tags page on the gateway shows execution time for the 1000ms to be around 50ms.

Thanks in advance for any advice!

I have received a few responses at another forum that suggest that a driver incompatibility is very likely.

Can anyone confirm if there are problems with v21.11 firmware and the Logix driver for 7.7.3? Can the driver be updated separately from the rest of Ignition?

I have been reluctant to update ignition and potentially break something. I have little time for the current project as is, let alone fixing the old stuff.

It’s sometimes possible to update modules individually within the same version series, but the latest Logix driver requires at least Ignition 7.9.5.

The Logix driver has a diagnostics page in the gateway that might shed some light on the current performance. Scan class execution times are irrelevant for OPC tags unless you’ve got the scan class in Read Mode.

Forgive my ignorance - the diagnostic page you’re referring to is the log? Or is there a separate page just for the driver? I’ve just set xopc.drivers.logix members from INFO to ALL so hopefully that will help zero in on the issue.