I have a Chaffoteaux Aquanext performance 200 water heater at home. This is the same as Ariston Nuos 250i.
I would like to use HomeAssistant to retrieve data exchanged on the serial bus between the main board and the user interface board.
Have any of you achieved this?
For the moment, I’ve plugged in a logic analyzer and I can see exchanges between the two boards. It communicate with a TTL Serial Protocol (5V), and with 9600 baud / 8N.
I setup an UART protocol decoder in PulseView Logic analyzer.
Hi,
as you already found , i documented quite a bit of the Protocoll on
Your Modell has more Software features like Timed Profiles etc. But you will figure out the missing/different functionIDs quite fast, by stepping through every Menu entry of your HMI Board with tre rotary knob ( including the Service Settings)
while recoding the Communication. Every time you enter one of the “L” Entrys you will get a resonse from the Mainboard with the display reading.
You can use any Serial Terminal Software, and by setting “automatic LF on CR” as in Putty the protocoll becomes easy to read/record.
So it should be fairly easy to get little ESP32 Program to continously read all the Data and forward it to MQTT or anything.
Without any effort you will be able to read whats on the display, e.g States and Target Temperature and Dome Temperature, as it is continously send (or continously requested by HMI).
For acessing the deeper insights, like all Temperatures (Air, all lower Watertemperatures, Evaporator Temp) you wil have to send Data in parallel to the HMI board.
This is the Part where i was struggeling with a PCB design. it would be fairly easy to passtrough the HMI->Mainboard communication trough ESP32 software in order to inject your own commands, but i did not like this idea as if the ESP32 fails/Board is disconnected it might influence the normal function of the appliance. I need something failsafe, as in my case my appliance is too distant away from me. I thought about breaking the communication with a reed relais only if neccesary, but as a non electronic professional im still stuck here in decissions. Also it was simple to experiment with the TTL/Serial interface, a long term connection should probably be galvanically insulated, etc…
Good luck and hope to see your findings in the repos soon.
I am also interested in joining forces for any ESP32 based projects for this.
Also what i was wondering, if the RJ12 Connector is really only for flashing, or if it you mabe also can access data there for servicing. My idea was, if so , maybe you can access the data with the same commands as HMI <->Mainboard exchange. But i did not have time to test this.
