I have a Honeywell EC65 boiler and a Siemens QAA70 thermostat and I’m hoping this is pretty similar as I’d established the BatiBus basis. I’d been intending reverse engineering to try and integrate with my own home automation system but it’s a tedious task so it never made the top of the list. This makes it so much easier.. thankyou.

At 65KW I too have an overpowered boiler as ‘recommended’ by my installer – so a lot of cycling every minute or so and even when heating water. It can’t modulate down low enough. I have plans to use a two coil tank to improve heat transfer into the water.

I’ll let you know how I get on , I use Pi’s and have a BeagleBone Black so some commonality there. Any further progress you have made I would be most interested in hearing about.

Also @Pasi – some of your English URL links are now broken – if you do have any updated ones that would be good or maybe I could contact you via email.

Cheers Kevin

I’ve since moved from radiators to floor heating, and that gives better results. I’ve had days with only 1 burner start, and a continuous burn throughout the day. But with the current weather (9ºC, little wind) it pulses on/off again.

If you can deliver a bidirectional channel between the bus and the RPi, you can simply use my scripts to generate the graphs I’ve shown in the blog post.

Thanks for the link. I think I read trough most of it back when I first started this project, but a lot of info was added since. Very interesting! It will be a good read this evening 🙂

coincidentally, I’m also picking this up again. I was going to log a lot more information, but I was unhappy with the duplex mismatch caused by my current design. So I’m re-implementing the communication protocol in the PRU of a BeagleBone Black. What are you planning to do?

To answer your question: indeed, these messages are only sent on-demand. I have my computer send the question-messages every minute, and record the answer.

I found an interesting forum (in German) that has reverse-engineered the protocol to a much greater extend than I did: https://www.mikrocontroller.net/topic/218643

Also, do you have any idea what the 3 bytes after the length mean? They must have something to do with the circuit number. I have 2 heating circuits and I see a difference in those bytes for the same requested values (same command bytes). I noticed that the second and third byte of those 3 get swapped between request and reply.

now all working ..

regards.

I’ve ordered a couple of JeeNodes to monitor my gas utility meter and the Elco-bus.

I assume you have my private email-adres trough this blog. I’m not sure it’s a good idea to post my github details here… In the meantime, I’ll start thinking about CSMA/CD and I’ll study the links in the replies above.

Merijn

I had the same goal: integrate my existing domotica system (Velbus-based) with the heating to get a more efficient end result. But I’ve apparently lost my drive halfway through… Anyway, I would gladly join forces!

I think the first step would indeed be to start monitoring your setup. In order to do that the correct way, I would suggest to go with the Arduino from the start, so you can have proper CSMA/CD.

If you provide me with your GitHub username, I’ll add you to the repository.