Using multiple IHDs causes minor usage data quirks between them - "mini bug report"


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Howdy!

This is a sort-of bug report but probably not something that’s worth fixing, given that very few members are likely to be able to trigger it and the very tiny impact that it causes. However, I wanted to mention it anyway so that it’s known about.

As such, I won’t be using my usual templates because this “bug” doesn’t fit very well within them.

Please note that everything in this writeup is only possible to pull off if you have more than one IHD paired to your meter(s). The tech specs for SMETS2 officially supports up to four IHDs being on the HAN at the same time, so my use of The Kecleon Brothers in this way is fully supported. If you only have one IHD, you won’t trigger this behaviour.

I’ve recently been upgraded to full SMETS2 and my new smart meter is nicknamed Raichu. I’ve also got two Chameleon IHDs that I nickname Kecleon Green and Kecleon Purple (aka The Kecleon Brothers when I refer to both at once). You can find full details of them in my forum profile. They prove useful for various purposes… :wink:

One of the things I’ve noticed is that when using both of the Kecleon Brothers at the same time, there’s sometimes a few minor differences/discrepancies in the usage data that they both report. In terms of Usage Now, I’m only talking a couple of Watts/Pence or so and for So Far Today/Week/Month/Year it’s probably also pretty small - but Raichu hasn’t yet logged enough data to hydrate anything beyond This Week, so I can’t fully check This Month yet.

On the plus side, the Kecleon Brothers do seem to be able to simultaneously download all of Raichu’s data in under 90 seconds whenever they’re connected, even though I can’t leave them running 24/7. So at least I can see everything that's been recorded. :wink:

I believe it's likely related to the fact that each IHD only polls Raichu once every 10 seconds and they seem to have to take it in turns. So for example:

  1. 11:03:00am - Kecleon Green polls Raichu to retrieve data for Usage Now and gets 125W and 1p/hr
  2. 11:03:05am - Kecleon Purple polls Raichu to retrieve data for Usage Now and gets 130W and 2p/hr
  3. 11:03:10am - Kecleon Green polls Raichu to retrieve data for Usage Now and gets 131W and 2p/hr
  4. 11:03:15am - Kecleon Purple polls Raichu to retrieve data for Usage Now and gets 121W and 1p/hr

And so on. I suspect Usage Now is more prone to this quirk than Daily/Weekly/Monthly/Yearly, but it's something that’s kinda fun to watch. It’s also worth bearing in mind that quirks like this will not mess up your billing or usage data and will definitely not break the usage graphs in MyOVO! I like to think of it more as a sort of an accidental Easter Egg that wasn’t considered when the SMETS2 spec was in development.

This isn’t really something OVO can fix as it’s reliant on external factors and would probably require changes to SMETS. Changes like that are kinda fiddly and would require too much effort for such a tiny bug/quirk (maybe a future SMETS3 might fix it, but probably won’t be in SMETS2). And that’s why I’ve asked for this not to be escalated. :wink:

However, if you do happen to have multiple IHD’s, feel free to have some fun and see if you can spot any other quirks! You can be sure that I will. :stuck_out_tongue:


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