Modbus RTU over TCP

[murik85]

Is it possible to add an "rtuovertcp" connection to the integration?

[trilobyte303]

this would be nice! i'm using a waveshare Modbus TCP to RTU converter connected to the Modbusport of my Deye inverter. Modbus is much faster and more stable than the Solarman LAN Logger.

[trilobyte303]

that works very well!

[trilobyte303]

after a restart of homeassistant the IP is set to the ip of the Solarman logger automatically. how can i prevent that?

[davidrapan]

Change the IP to waveshare device, enable debug logging, restart the HA and attach the debug file from after the restart here. I'll look into it.

[40federico]

I am trying to do the same with a waveshare device and this is the error message loading the configuration:

Failed setup, will retry: Error setuping Inverter_m: RuntimeError('coroutine raised StopIteration')

(I have 2 inverters in parallel. By the moment doing games with the master only)

[TSA-lab]

Same for me with Elfin EE11a - similar device to Waveshare.

#575 (reply in thread)

[davidrapan]

Hi @murik85, isn't Modbus TCP enough? Do you really need this special case of RTU over TCP?

[murik85]

Yes, it would be very good.

[davidrapan]

What device supports only this mode?

[murik85]

I just want the data not to be transmitted to the remote server. You can certainly block/change the IP servers but this is a "crutch".

[davidrapan]

I'm confused. What this have to do w/ cutting off cloud servers?

[trilobyte303]

home-assistant_solarman_2025-06-07T17-19-32.747Z.log

started the logging of the solarman integration. did a restart of HA.
Ip of the solarman LAN Logger is 192.168.1.64, the ip of the waveshare RS485 to Modbus TCP module has the ip 192.168.1.254.
the port is still 502, but the ip is set to the ip of the logger

[davidrapan]

Try to remove the device and add back again using waveshare IP.

[trilobyte303]

I don't quite understand what I should do? delete the solarman integration and recreate it? or unplug the LAN Logger or Waveshare and plug it in again?
if i have to reinstall the solarman integration, will i not lose any data?

[davidrapan]

Not the entire integration, just the device within.

[davidrapan]

Hey @murik85, feat: Add support for Modbus RTU over TCP should work but try it and let me know. 😉

[scruysberghs]

great work @davidrapan .
Now all we need is support for modbus serial (usb stick) and your integration with the plugins would be the ideal replacement of the default modbus implementation in home assistant (https://www.home-assistant.io/integrations/modbus/#example-typical-serial-configuration) and actually make modbus usable in home assistant

[davidrapan]

Going outside of IP stack would be too much, imo. And you can setup Modbus serial <-> TCP proxy quite easily.

[scruysberghs]

I did just that using the "Modbus TCP to Modbus RTU Gateway Add-on" home assistant add-on from https://github.com/kellerza/sunsynk (mbusd - https://github.com/kellerza/sunsynk/tree/main/hass-addon-mbusd). Works like a charm with these settings for the add-on:

And than these settings in solarman:

[TSA-lab]

Thank you, this helped me a lot. I try to connect to a Deye 10k 3 phase via an Elfin EE11a Modbus to TCP adapter (192.168.33.50). It has worked with this Elfin config and with the integration [of kellerza.] (https://github.com/kellerza/sunsynk) and in my case no RTU to TCP proxy is needed, because the Elfin provides already Modbus over TCP.
Elfin config:

solarman-sticklogger HA device config:

And I get this initialize error and don#t find any logs about this:

Any hint for me to solve this?

[trilobyte303]

i use this settings:

[TSA-lab]

Thank you for your reply

So no flow control vs half duplex is the only difference I can detect?
But this depends on the Modbus interface of the current inverter. You use also Deye 3 phase?
This half duplex already worked for me between Deye -> elfin EE11a -> kellerza/sunsynk integration -> MQTT HA

[davidrapan]

@TSA-lab, what the debug log says?

[trilobyte303]

i'm using a waveshare RS485 to RS485 converter and a deye 3ph LV Hybrid inverter

[moonsorrox]

I'm also using this Waveshare, just like @trilobyte303.
All the settings are the same except for the IP and MAC addresses.
My problem is that I've already tried all possible register addresses with Gemini, since I have a brand new
Deye SUN-15K-SG05LP3-EU-SM2.
Unfortunately, there are very few Modbus addresses available.

I've found a few:
Deye Daily PV Production - 529
Deye PV Power String 1: - 672
Deye PV Power String 2: - 673

That's basically it.
It's very tedious. I also have the Solarman Home Assistant integration, but it shows as unavailable for about 1-2 minutes.
Then the values ​​reappear, and this goes on indefinitely, which I really don't like.
But of course, I have all the values ​​via the logger.
Why do the values ​​keep disappearing?

[davidrapan]

Hi @moonsorrox, this model uses exactly the same register ranges as the previous one, so simple use this integration to monitor and control your device. :)

[moonsorrox]

Okay, but how do I get the data into Home Assistant via Modbus using my Waveshare module?
The logger is registered, but as I mentioned, it doesn't display anything for several minutes.
Then it shows data for less than a minute, and then nothing again.

The data is much better via Modbus, but I don't know that yet.
I'm not very familiar with the Waveshare module.

@trilobyte303
Perhaps you could tell me how you process the data?

[davidrapan]

You need to select Modbus TCP (instead of plain TCP) as the transport protocol and set the correct port.

[moonsorrox]

Wow... thank you so much for the explanation.

Now the data is coming through correctly.
I entered the Waveshare IP address, set the port, and entered the protocol you mentioned – everything's perfect.
THANK YOU, THANK YOU

[davidrapan]

Sure thing! 🎉