Hub stops responding to devices, have to restart hub

Over the past few weeks I've had 3-4 occasions where Hubitat stops responding to button pushes, and I have to restart the hub to get things back to normal. Nothing I can think of has changed on my end except for performing hub updates.

The first couple of times it happened I noticed I was able to get into the dashboard from my phone and change the mode. I ended up power cycling the hub to get things back to normal.

This morning I did a little rudimentary testing and it may be a Zigbee radio issue? I pressed multiple Zigbee remote buttons, the events for the devices aren't showing up in the hub. Zigbee contact sensors also not triggering in the hub. Pressed a couple of hard wired z-wave devices, and the events did show up. Was able to log into the control panel and restart the Hub.

I can do some more testing next time it happens to try to narrow things down, but wanted to get this out there and see if this is a known issue, or get any advice on what to check.

No known issues. But it sounds like a rogue zigbee device that might be flooding the mesh.

You can do a quick check by disabling half your devices in the device list (X top right in table view) and see if the problem still occurs. If so, keep cutting it in half until you find the offending device.

Or if you suspect a single device, you can narrow it down by temporarily disabling that device and see if the issue goes away.

Are these devices using built in drivers or community drivers?

It would help to list out the devices and drivers you are using, as maybe others also are using those with no issues and that could help narrow down the issue.

Also, interference can also cause similar symptoms. Are any of these devices near potential sources of interference? Microwaves, metal casings, wifi access points, other wifi devices, etc.?

The last potential cause, is the lack of repeaters or a saturated repeater. How many repeating (AC powered) zigbee devices do you have between the end device (the button) and the hub?

Most repeaters are limited to 6 end devices. So if you have more end devices, battery powered than 6 and only 1 repeater, you may have signal issues. This makes the ideal ratio of battery end devices to repeaters around 6:1 but it also depends on arrangement of repeaters too.

All of the devices are using built in drivers.

I did just realize that I moved my Hub closer to my wireless access point recently. I moved a Zigbee device to a corner of my house, and it wasn't working reliably, so I move the hub about 6" to a higher shelf to get better range, which put it withing about a foot of my WAP. I'll put it back and see if the problem persists.

That sounds like you have an issue with your mesh and not enough repeaters in your network. 6'' really shouldn't make a difference if you have enough repeaters

Yes but 12" from a wireless access point would cause interference.

Also, just because the devices are using built in drivers, doesn't mean they are compatible or can't be bad actors on a mesh either. Some Zigbee devices don't follow the standards that our generic drivers follow and require a custom driver to function properly.

Of course, the past logs or live logging is also incredibly helpful in tracking down bad drivers or devices as well.

What distance between an ap and the hub would you recommend?

Section 3 of this white paper,_Thonet.pdf presents the results of several studies of Zigbee/wifi coexistence; the recommended distance to wifi interferer varies with the degree of channel separation. Schneider Electric's test result recommends 1 meter distance to a wifi inteference source and a channel frequency offset of at least 30Mhz. Looks like most studies agreed on 1 to 2 meters as a recommended distance.

Several interesting experiments are described in that document. In most cases even in the presence of severe interference the packets can get through but latency due to retries becomes an issue.

1 Like