Values flicker from good to no good sporadically

Hi Guys,
First time poster here, and I am very new to Ignition (have only made changes to a project, have yet to do one from start to finish). If more information is needed, please let me know.
Here is the revisions of what I have running:
Ignition Version: 8.0.12
Operating System: Windows 10
Java Version: 11.0.6+10-LTS
For connections I have 12 ModbusTcp devices and 2 CompactLogix devices.

For some reason one of the clients is “flickering” between a good tag value and bad one, if that makes sense. Please see the attached video. The tags in the video are being polled from one of the ModbusTcp connections.

From what I can tell, it flickers for 15-30 seconds, then is ok for a day or two. (I am going off what the plant operators are telling me I am only onsite once every month or two).

If any logs or additional information is needed, please let me know.

While I am not sure what is happening, it looks like the tags are getting into an uncertain status at least temporarily.

Are there any additional messages in the Ignition log file? (data/wrapper.log file on your Gateway server)

If it is the same tags the consistently run into this issue, it might be worth adding a Tag Event Script to the tags showing the issue that will log what quality value you are seeing and narrow down when it is occurring.


Check the load of the Tag Scan Classes / Tag groups (maybe are not running at the appropriate speed for the process or for the plc), as well check the Tag Load factors, if the PLC is overloaded or the response slows down, it can cause that sporadically and without creating logs.

Thank you both for your interest. I am currently off site. I have a trip planned for next week and I am going to dive into this a little more. I will update here with what I find.
Thank You