While doing some testing on an IP changing script I found a strange behavior in the quality of the tags.
I had written a script that would take two IPs, main and backup, if my watchdog didn’t update the comms would fail and the script would attempt to change to backup comms.
While testing to see if it would work, I connected a DNP3 outstation to the main IP and had no device connected to backup, as I just wanted to check if it would change properly.
The device IP changed well, but when I executed the script in quick succession in the script console and the left it alone a strange pulsing of bad quality occurred after the device connected.
Essentially all of the tags on the station would flicker between good and bad quality changing maybe twice a second in quick speed, or holding on bad quality. However when I updated the tags in the PLC, the tags on my Ignition would update. I can even write to the tags in bad quality and have it update on my PLC as if the tags was good quality.
This is similar behavior we have noticed in poor quality 4G comms on some of our remote sites.
How exactly is bad quality measured in Ignition, and why is that it seems to get stuck in this loop.
Note- When checking Wire Shark the tags appear to be communicating normally, restarting the driver on device configuration doesn’t fix this issue. The PLC and outstation are wired into my server with an ethernet cable and I can replicate this result, though how long it lasts varies.