Oddity with AEOTEC Gen 5 stick going offline

No changes to my system, it has been working fine. RPi4 computer. A few days ago, the ZWAVE controller went offline for no apparent reason. A reboot fixed it. At this point, I wanted to add some logic to alert me to the situation, which I have been able to do. I receive a Telegram notification if the temperature sensor is no longer updating (which is a strong indicator that the controller is offline). This works, but I have found no way other than a reboot to remedy the situation — if is almost like once the error condition is raised, all communication ends until I reboot the RPi.
Questions:

  1. is a reboot truly the only way to remedy this?
  2. Any ideas as to the root cause? By the time it happens, the log has already wrapped so I don’t have good insights — any suggestions as to how to address the log losing visibility (all lines are blank) ?.

Thank you, in advance,

  1. It might be sufficient to restart the Zwave binding through the karaf console. Not knowing what the source of the error is it’s impossible to say if that will work or not.

  2. Monitor the zwave controller Thing. You can trigger a rule when that Thing goes offline to tell you when the controller goes offline. That should give you timely alerts so you can go look in the logs before they’ve wrapped.

This is a known issue with the Aeotec Gen 5 stick not working properly with a Pi 4. The short version is that the stick is not fully USB compliant. Most people (myself included) found that the stick would not be detected at all when plugged into a Pi 4. The work around is to connect a USB hub in between the stick and the Pi. There is also a hardware modification for the stick that is supposed to fix the problem although it did not work for me. I am running the stick through a small USB hub and it works OK.

Here are some links for a more detailed discussion of the problem:
https://forums.raspberrypi.com/viewtopic.php?t=245031