Modbus TCP with Fronius Symo Inverter to control Export Limit

Add-ons Bindings
1

Does anyone have the detail to set this up? I cannot get it working by using the 3 phase inverter thing in sunspec, so i tried the data thing and that didnt work either. I stuffed around with many options to no available. I tried a poller thing and then some data things as well, it all comes online with linked items but when sending the items number commands nothing happens to the inverter limit.

I’ve got IP connectivity and can change the export limit fine using the Fronius web UI but cant via modbus tcp

Any help would be great! Thanks

2

I do this with a Fronius Primo inverter - I suspect the parameters may be the same?

I have the following:

Modbus TCP Slave

Modbus TCP Regular Poll (the Slave is the bridge)

Modbus Data with register 40242 read/write uint16

Modbus Data with register 40246 read/write uint16

To limit the inverter, My rule does the following:

items.Fronius_WMaxLim_Enable_Value_as_Number.sendCommand(0);
items.Fronius_WMaxLimPct_Value_as_Number.sendCommand(requiredSolar);
items.Fronius_WMaxLim_Enable_Value_as_Number.sendCommand(1);

3

Note I’m not setting export control - I’m throttling the inverter directly….

4

Yes this i what I want to do, throttle directly. I cant seem to find the register, ill try modbus tester tomorrow when theres sun as i understand the datamanger shuts down once the voltage drops

5

Hey Paul, do you have a screenshot of your DNO editor inside Fronius data manger? I cant seem to try and control the inverter using modbus tester before I even try with the modbus binding…

6

Here you go. I do remember having to do do something to enable modbus control….

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7

There’s also this section on Modbus (on my inverter at least):slight_smile:

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8

Perfect, mines 100% identical. So you set your Priority to 1 for Modbus and note your set your Sunspect model type to float. (I was on int / sf)

9

I set this all up 2+ years ago - I’m sure I followed some kind of guide - but sing out if you need me to check anything else.

10

All good. Ive tried but just cant get the thing to drop power, seems the registers are different… driving me up the wall!

11

Fronius GEN24 - Modbus TCP and RTU Operating instructions appears to be the docs…

Specifically Fronius GEN24 - Modbus TCP and RTU Operating instructions

Searching on WMaxLimPct suggests the register is 40242 same as mine…

1 Like
12

Thanks, its finding the registers though thats my issue.