"Virtual" Device, Data Fed via ModbusTCP/MQTT

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sim-1 asked Feb 3, '24

"Virtual" Device, Data Fed via ModbusTCP/MQTT

Hi,

I have a SmartSolar PV controller connected to Venus Pi via VE.direct. I also have a control system that has MODBUS TCP client coded and I successfully communicate with Venus to read battery volts. This system also activates supplemental battery charger which provides data via proprietary protocol.

Goal: Consolidate the energy used by battery charger in one place with the data of the SmartSolar (PV power and load usage).

Is there a way to add a virtual device in Venus, preferably with holding (read and write) MODBUS registers that I can "feed" from my control system? I don't think my control system has a module to be MODBUS master, but if there was would that work?

Alternative could be via MQTT, but I am yeat to experiment with that.

Venus OS

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Modifications Space

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Answer 1 · 2024-02-07T10:16:48Z

matt1309 answered · Feb 07 at 10:16 AM

Hi @Sim

I think this is what you're after:

howto add a driver to Venus · victronenergy/venus Wiki · GitHub

Here's an example script: velib_python/dbusdummyservice.py at master · victronenergy/velib_python · GitHub

I believe if you use a existing dbus path from below link that it setups up MQTT topics correctly for you.

dbus · victronenergy/venus Wiki · GitHub

I've never tried ModbusTCP but i imagine it's handled the same. Adding completely custom device might be a bit more involved, but i think it does cover that in the "how to add a driver to venus" link i shared above however I've never tried that.

I have used this for method for getting an old radio oil tank sensor into venus. I have a raspberry pi capture the radio frequency of the oil sensor then send it via mqtt into venus os which has a virtual tank sensor script installed using the method described above. The only change i needed to make to dummy script was service name change to

com.victronenergy.tank.tty01

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