Fronius PV Inverter with grid meter

English Forum
1

I have a fronius symo inverter. If I connect to openems via modbus over TCP, it reads correctly the production value from the inverter. However, I have a (Fronius) smart meter which measures the grid connection, and it is connected to the inverter via modbus over some wires (so not on the home network).

How can I get openems to read that grid power value out? it is supposed to be Modbus device id 240 on the inverter.
Is there a ready made component in openems which I can use? (I did not find a generic modbus power meter)
Do I have to implement a new modbus meter class? Do I have to work on the Fronius PV inverter class such that it also acts as a grid power meter?

2

Hi alagi,

thanks for getting in touch!

So if I understand you correctly, Fronius provides the meter data via Modbus/TCP on Unit-ID 240. If this is true, you should be able to copy the code from the SolarEdge Grid-Meter implementation (https://github.com/OpenEMS/openems/blob/develop/io.openems.edge.solaredge/src/io/openems/edge/solaredge/gridmeter/Config.java).

Regards,
Stefan

3

Hello together,
Has anyone worked on this topic and can share their results so that no work is duplicated?

If I understand correctly, a completely new metre must be created, right?

Best regards,
Maik

4

Hi Maik,
there is an open Pull Request (PR2150) on the Fronius Gen24 Symo. I don’t see a meter implementation in it, but it could be a good starting point for you.

Unfortunately we were not able to make it a fully working ESS in OpenEMS. But in principle it should be possible, see this post

5

Hi Christian,

I have implemented the meter (Modbus RTU) readable via the Fronius Gen24 Symo (Modbus TCP).
I will now test your pull request, I only want to monitor the Gen24 in first step so it should work well.

Thanks for your answer

6

Hi @Maik,

did the implementation work for the Gen24?

Thanks a lot
Raphael

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7

Hi all,

I am currently implementing support for another brand of inverter (Huawei) that can have an integrated grid meter.

The approach mentioned above (for SolarEdge) seems sound, but my question is how to use it in practice.

For the Huawei inverter, the grid meter data points are available on the same Modbus interface as the inverter data points. (I.e within a different defined register range).

Therefore, if we take the above approach of creating 2x OpenEMS components (1 for grid meter, 1 for inverter), will we pass the same Modbus bridge to both components?

I think this approach will work but I wanted to check if there will be any issue sharing a bridge between components.

Thanks,
Thomas

8

Yes, this will work reliably. It’s one of main reasons, why Device-Component and Modbus-Bridge were split in the first place, and can be found in many devices (e.g. GoodWe Battery-Inverter).

Regards,
Stefan

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