Modbus address configuration

[patrickvorgers]

I have a Eastron SDM630 kWh meter connected to my Deye inverter 12KSG05. I would like to reuse this meter also for my SmartEVSE setup because it is already measuring the 3-phase currents. The Deye enforces the Eastron to have modbus address 1. This address is part, as I understand it, of the restricted addresses of the SmartEVSE setup (0-10).

Is it somehow possible to make the modbus addresses used by SmartEVSE configurable so that I can free up address 1 and use it for the Eastron meter?

[thmjanssen]

You cannot have multiple Modbus masters on the same bus. So your intended design will not work properly regardless of the modbus address.

[dingo35]

I am installing that same configuration, but I am connecting my Eastron to my SmartEVSE, that feeds HomeAssistant, and Homeassistant will feed the Deye.

As thmjanssen says, modbus can only have 1 master per bus, and Deye and SmartEVSE both want to be master.

An alternative solution is to connect all modbus devices via modbus-to-ethernet gateways (1 per device) to your lan, that way you have ultimate connectivity.

[patrickvorgers]

@thmjanssen and @dingo35

I will be using a modbus gateway for that issue of multiple masters. It will buffer requests from masters (if needed) and send it to the slave. With this you can have multiple masters requesting data from a slave.

@dingo35, my goal is to have the setup independent from Home Assistant so that it keeps working even if Home Assistant is turned off.
How would the setup with modbus-to-ethernet gateways look like? Wouldn't I still run into the address issue?

[dingo35]

Every modbus device would have its separate modbus to its individual gateway; its been done before, look at the Deye topic:
https://gathering.tweakers.net/forum/list_message/84578370#84578370

[patrickvorgers]

I am using this to connect my Deye to my Home Assistant instance for the Sunsynk addon which reads the modbus registers from the Deye. I could also use this for the Eastron (need 2 - master and slave) but how would this resolve the address issue? I presume that the Deye still expects the Eastron to be on address 1 and if I add the SmartEVSE to the mix, it would expect the Eastron to have an address greater than 10.

Maybe I am missing something here?

[dingo35]

Unless that device is able to remap the modbus addresses, which I dont think it can, you are right, that device is not solving your problem.

[patrickvorgers]

Is it easy to modify the firmware to get a custom firmware that frees-up address 1 or are there a lot of dependencies in the code?

Maybe an alternative would be to use the RS485 on my Waveshare ESP32 display (already in the charger for a custom UI) and have the display use the API on the SmartEVSE to set the current. I would use the API interface because MQTT would create another dependency on the MQTT-server that needs to run on my network.

[mstegen]

I've had not much success with a isolated 4 to 1 modbus master HUB (E810-R41) . Resulting in frequent modbus timeout issues. But this was before the timeout was increase to 150ms, i need to re-test this.
But like @dingo35 mentioned, this will not solve the modbus address problem. Only if you can somehow change the address you might be able to use this.
Unfortunately the addresses 1-10 are reserved for node controllers(1-8), broadcast (09) and the sensorbox (10)

My Deye menu however has some settings in the Advanced menu:

• EX Meter for CT checkbox
• An address field

I use the CT clamps with my Deye, so i'm unable to test this myself.

[patrickvorgers]

I think I can try to do some modbus remapping in my ESP32-S3 which is driving my screen.
Good point to check whether I will run into timeout issues because the chain would then become:

SmartEVSE -> Display ESP32 - used for remapping -> HUB 3 to 1 -> Eastron

I tested on my Deye and in the UI you can set master/slave modbus addresses but that is used for letting multiple Deye's communicate to eachother. The modbus address field is above the EX Meter for CT checkbox correct?

[mstegen]

Yes, the top of the menu is for inverter to inverter communication (or in my case: esp-home to inverter, so i get the inverter data in HA)

On the bottom however, i see the following:

This option might be firmware dependant, i'm running a quite old firmware on the inverter.
Now i'm thinking about this, it could also be a numerical representation for a Eastron or Chint kWh meter. In that case it's not possible to change the address for the meter.

[patrickvorgers]

That's indeed for the selection op de type of meter (see screenshot of my inverter)

[dingo35]

As long as you dont mind fiddling with ESP32's, this project might interest you:
Interface Deye <-> modbus esp32:
https://github.com/M4GNV5/esphome-deye-modbus/

[patrickvorgers]

Thank you, I will have a look at it.

For now I am investigating whether todo the remapping in the display controller. I will update my findings here.

EASTRON -> (RS485) -> Modbus gateway -> (RS485) -> Deye
                                     -> (RS485) -> ESP32 Charger display - remapping -> (RS485) -> SmartEVSE