Supporting Hitachi Heat Pumps / Hitachi Modbus Gateway Replacement

[mrtnkhl]

Hi @lumixen

Great work on this, love that you are building an H-Link interface based on the ESP32 and ESPhome, thanks!

There is another cool Hitachi / Home Assistant project by @alepee https://github.com/alepee/hass-hitachi_yutaki that makes indirect use of H-Link connecting to an Hitachi H-Link to Modbus gateway ATW-MBS-02 to interface with Hitachi heat pumps (Yutaki, Yutampo, etc.) for domestic hot water, (floor) heating, etc.

It would be amazing if your work on an open source H-Link interface could be used to replace the expensive Hitachi Modbus gateway with an ESP32 that would be more cost effective and most likely way better than what Hitachi has developed.

I assume one would have to understand what communication happens on the H-Link bus when the Hitachi Modbus gateway communicates with the Hitachi heat pump while specific registers are queried or set. Based on that we would need some form of abstraction on top of your code that provides a Modbus TCP interface or creates some other form of interface that @alepee can connect to with his code.

Creating this issue as a placeholder / space to exchange ideas on the above. I am sure @alepee has some thoughts as well.

[lumixen]

Hi @mrtnkhl,

Thank you for sharing your ideas!

Have you seen the HLinkSniffer project? It is designed to sniff Hitachi Yutaki heat pump communications. At first glance, it seems that Hitachi has several different protocols that all share the same name, "H-Link". If that's the case, this ESPHome component would likely be valid only for Hitachi air conditioners.

I also encourage you to use Discussions for questions, ideas, feedback, etc.

[mrtnkhl]

Hi @lumixen

Yes, I have seen the HLinkSniffer, I will have a look at the bus when I get a chance later this year.

Thanks for your work!