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Can I turn off the HAN function on my smart meter to stop interference with my zigbee network?

  • 3 December 2021
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I have 30 or so zigbee home sensors/devices in my smart home network. I discovered when I added a new outdoor sensor and zigbee router near my smart meter that there is interference. Rather than change my home network to another 2.4 GHz channel I would like to switch off the HAN function of my meter entirely. I have a pipit display but do not use it.

Is there a way to disable the zigbee HAN on the meter or remotely?

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Best answer by Blastoise186 3 December 2021, 13:13

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Howdy @kryten !

Unfortunately not I’m afraid. The ZigBee HAN has to remain active even if you’re not using it, and there’s no way to disable it at all. Not least because most Smart Meters communicate via the same HAN even if you’re not using the IHD - it’s pretty rare for even the electric meter to communicate via a hardwired connection.

I’m actually surprised you’re getting interference as well, since ZigBee stuff is supposed to be capable of automatically changing channel to avoid interference from Wi-Fi and other ZigBee devices that aren’t on the same network. Likewise, Wi-Fi and ZigBee are supposed to play nice with each other, so this is kinda strange.

You might want to see if you can have your other devices switch channel if possible - but they should be automatically doing this by default. If you’re changing Wi-Fi channels, the best ones to use are generally either Channels 1, 6 or 11 for Wi-Fi. An app such as Ubiquiti WiFiman can also scan the environment to help you see what’s nearby and pick a good channel to use for Wi-Fi, but it can’t do ZigBee because of hardware compatibility.

The only other thing I can think of is that something in your environment isn’t playing fair or playing by the rules. You might want to investigate whether that ZigBee router could be a possible culprit. Changing the settings so that all your 2.4GHz networks run on 20MHz Channel Width rather than 40MHz Channel Width will also help as well, since it reduces conflicts and frees up more bandwidth. 5GHz isn’t a problem though as there’s loads more space - you can even run 5GHz on 160MHz Channel Width without issue, as long as you’re careful with the channel selections.

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Hi @Blastoise186 

Thanks for your speedy reply!

I read quite a bit about zigbee vs wi-fi interference when I was planning my network and kept the channels well separated. All was well until I discovered this problem with the smart meter. If it’s using channel 11 it will interfere at the default radio frequency - media layer and I believe zigbee 2 isn’t sophisticated enough to switch channels. At least, the Z-stack software on my CC2531 coordinator has a fixed channel allocation and that’s it. The sensors probably aren’t that clever either.

This will be quite a nuisance for anyone who uses Smarthings/Phillips Hue etc. etc and they probably won’t have a clue what’s going on. The only saving grace is that it’s outside the house. 

I tuned my Ubiquity Unifi wi-fi network to avoid channel 11 and it co-exists nicely with my zigbee network. Looks like I’ll have to find another frequency hole in it to shift my zigbee kit to and then re-pair all the devices. What a pain!

Maybe I’ll just get lots of silver foil and line the meter box (I jest, of course).

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I had a feeling you were using UniFi somehow. Great minds think alike then! I have a very overpowered setup with loads of the stuff. XD

In that case, try using one of your APs to run an RF Scan of the environment, which can take up to five minutes and will take the AP offline while the scan is in progress. You can trigger this from either the web UI or the UniFi Network app by going to Devices > Select an AP > Insights > Scan Channels if you’re in the web UI. Otherwise in the app it’s Devices > Select an AP > RF Environment > tap the refresh button in the corner.

That should give you some insights as to what your APs are seeing, just in case that data can help. If you plan to run RF Scans on all of your APs, I’d recommend doing it on a rolling basis by triggering the first one and then waiting for it to finish before triggering another. You might also want to consider the Wi-Fi Ai feature as well, since I find it does a great job of making UniFi kit dodge basically everything. It might not work for your environment, but you can always turn the feature off and go back to doing it manually if needed.

But here’s the good news. You can also set Wi-Fi Ai to explicitly blacklist specific channels from being selected automatically. For obvious reasons, the default blacklists include channels known to cause interference, but you can also add more if desired, such as Channel 11 on the 2.4 GHz band. That way, you can make sure the controller never picks channels that are being used by your ZigBee kit, while still taking advantage of automatic optimisations of your APs.

Your controller will keep records of all changes made by Wi-Fi Ai, so that you have a full audit trail and can revert back to any snapshot at anytime. Helps with diagnostics!

And yeah, I’d agree with you there as well. Ubiquiti UniFi seems to have some of the best automatic optimisation features out of basically anything, so if it can’t play nice with ZigBee… Then good luck making those cheap £20 value “free” ISP Routers do it! :D

But unfortunately, even UniFi can’t fix ZigBee stuff misbehaving - the best it can do is try to get out of the way to attempt to keep the WiFi Experience scores up while not killing everything else. If your Philips Hue lights decide to bully their way through and bulldoze everything else anyway… You’ll probably want to yell at Philips about that!

Smart Meters however, are meant to be ZigBee Certified, so they should be playing fair with everything else - and that includes collision avoidance. :)

Otherwise, the only other alternatives would be to switch to using kit that supports either Z-Wave or Matter rather than ZigBee, since these are designed to run on dedicated frequencies that are guaranteed never to clash with Wi-Fi or ZigBee.

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I remember using that scan feature once before - it’s quite respectable. Good idea to use it in this case.

Any externally served smart home service has to earn my trust. Hence my home-grown zigbee network linked up to Home Assistant. So I have shunned almost everything I can’t control from my own server. It was a shock to find my energy supplier had dug a trench under my battlements. Still, it makes for an interesting life.

Thanks again for the suggestions.

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No worries. :)

Home Assistant can also support Z-Wave as well. It’s not a built-in feature per se, but there are add-ons you can install which can do it. How you install them however, depends on how you host your instance. If you’re on a RasPi for example, the one you’re after is in the add-ons store. If you’re using Docker though, you’d need to spin up another Docker container with the add-on and then link them.

And obviously, you’d need a physical Z-Wave hub plugged in as well. :D

You’re not the only one to do this however. We’ve actually got a fair few members who use Home Assistant on the forum.

And yeah, given that I’m using a UDM-Base, AC-Lite, nanoHD and U6-LR in my setup (which is a one-bed flat!), I definitely make use of WiFi Ai to keep the neighbours happy. Perhaps not surprising that my setup still completely crushes pretty much everyone else nearby though.

Userlevel 7

Get the answer you were looking for, @kryten?

 

I’m sure @Blastoise186 is well deserving of some ‘Best Answer’ points for this one (I won’t pretend to keep up with the technical details!)

 

Also we’d love to hear more about this:

 

 

Any externally served smart home service has to earn my trust. Hence my home-grown zigbee network linked up to Home Assistant.

 

We’ve had some fellow Home Assistant architects here before and would love to get your take on the best way to get things linked over here:

 

 

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I think you are asking how to organise help topics around this on the forum?

It’s important to understand that Zigbee is a widely used low energy networking protocol that shares the 2.4 Ghz band with older wi-fi devices. It is distinct from, but similar in usage to Z-wave. Some smart meters use the zigbee protocol and thus have the potential to interfere with wi-fi and other zigbee devices.

Ovo should publish tech info about this including the channel used, any ideally incorporate a way to switch it off.

Home Assistant is only one application which interfaces with zigbee but deserves the crown as the most prominent and accessible one (IMHO). Most manufacturers recommend using their own hubs (e.g. Hive, SmartThings, Ikea) to talk to zigbee devices but this is not the only way, and for those who are privacy conscious and also don’t want to rely on external computing resources & the internet to run their home, it’s arguable that they are not the best way.

You might want to open a forum on just those issues, but as a plea from me - please recruit a smart meter engineer for the project.

 

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Unfortunately, this kind of functionality is beyond OVO’s control. And even if OVO was capable, there’s no guarantee that all suppliers would be able to do it - so it’d be impossible anyway. I’m well versed in how ZigBee, Z-Wave and Wi-Fi work as it’s part of my job to know these things.

The only parties that could theoretically make this possible, would be the equipment manufacturers and DCC. But given that all Smart Meters in the UK communicate over ZigBee (even the electric meter), it’s impossible to disable the ZigBee HAN and still retain Smart functionality. There’s also no way for OVO to know what channel the ZigBee HAN is running on - especially for SMETS2 - because that functionality lies within the Comms Hub, which suppliers cannot access or control directly.

The best I could do is see if Tim or Jess can reach out to one of OVO’s internal Smart Meter experts and ask if they know what channels are being used. However, it’s probably impossible to provide that information, especially given that ZigBee likes to channel hop and is supposed to avoid interference. In addition, the config for your site will almost certainly be different from someone else, so a blanket thing of “please keep Channel 7 clear” won’t work in all cases.

I’m really sorry, but that’s probably the best we can do via the forum.

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@kryten  wrote:

Some smart meters use the zigbee protocol and thus have the potential to interfere with wi-fi and other zigbee devices.

I did publish some information about ZigBee and WiFi channels in March 2018 - within a week of the SMETS2 Smart Meters being issued for general installation.

Have a look at what I said then, and tell us if you feel this is still reasonably accurate.

The diagram is my own and can be amended without copyright issues.

If you think we need that explanation expanding, then by all means let’s agree on an update… on condition that it can be understood by mere mortals of course. @Blastoise186  speaks fluent hexadecimal and isn’t a representative sample of the average readership on this Forum. :wink:

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Thanks for the info (just to be clear @Blastoise186 my last post was in response to @Jess_OVO who seemed to be asking for an opinion on the info available on the website). Your technical input is much appreciated, though.

Thanks also @Transparent for your links. Yes, your info tallies with my understanding of  best wi-fi vs zigbee practices. The term ‘Channel Agility’ caught my eye and I’ll need to read more on this. I know for a fact that my CC2531 co-ordinator with Z-Stack drivers has no channel agility so I’ll be relying on the smart meter to ‘get out of my way’ if it can indeed do this.

From the IEEE source address on my meter I can see that it is manufactured by American firm Itron and I note that they sell into different international markets. So, to protect their interests in observation of varying radio regulations there will be a way to switch off the zigbee transmitter. Possibly the UK models have an ‘ON’ config baked-in at manufacture or installation. Who knows! A rabbit hole to avoid, I think.

For now, I’m relying on a DIY Faraday cage with strategic gaps to allow the the meter to phone home.

 

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