Daikin pinout information?

[matteius]

Howdy -- I found this project in my own initial investigation towards combing a raspberry pi pico w with my Daikin heat pumps. I have two CTXG12QVJUS heads, and here are some pictures of the connectors and my thoughts about them. Please disregard the dust, I did clean the unit after taking this photos.

Here we have the main power and two black connectors. I am not sure what the longer connection is, but I suspect that the 4 wire connector to a 5-pin (one is unused) is some kind of P1,P2 Power and Ground but I am not sure if this is accurate, or if true what the exact pinout is. I suspect that the right two pins are power and ground (not sure the order), but any insights would be helpful.

There is also this multicolor cable which I believe is a thermostat cable and not going to provide the functionality I am looking for that communicating with the P1P2 modbus would provide.

I am equipped with an Eagle license and just had my first board fabbed for a different project that came out nice. This is the next most important project I could apply my side electronic skills to. I found a micropython modbus library https://github.com/alejoseb/Modbus-PI-Pico-FreeRTOS and plan to grok this code at some point to work on a micropython version. However I am currently blocked on making 100% sure I know what I am connecting up to. Also would be interesting to know what the power coming off that connection is, because if it were 5V I would love to power the pico circuit with it as well.

[gmcmicken]

It looks like that unit uses s21 protocol, which is different from the one covered by this library.

[Arnold-n]

Indeed, this looks like a S21 serial connector.