Python library for connecting to Huawei SUN2000 Inverters over Modbus

This library implements an easy to use interface to locally connect to Huawei Solar devices over Modbus-TCP or Modbus-RTU following the 'Solar Inverter Modbus Interface Definitions' provided by Huawei.

It was primarily developed to add support for Huawei Solar inverters to Home Assistant, resulting in the following integration: wlcrs/huawei_solar.

Supported devices:

• SUN2000 inverters
• LUNA2000 batteries (when connected to SUN2000)
• EMMA
• SCharger (when connected to EMMA)

Features:

• Modbus-TCP support: connecting to the inverter via the SDongle, EMMA, or over the WiFi-AP (SUN2000-<serial_no>) broadcasted by the inverter
• Modbus-RTU support: connecting to the inverter via the RS485A1 and RS485B1 pins on the COM port
• Batched reading of Modbus registers and converting them into the correct units
• Reading Optimizer data via the specialized 'file' Modbus extension
• Writing to Modbus registers (mostly useful for setting battery parameters)
• Performing the login sequence to gain 'installer'-level access rights

Installation

This library is published on PyPI.

Basic usage

The library consists out of a low level interface implemented in modbus_client.py which implements all the Modbus-operations, and a high level interface in huawei_solar/devices which facilitates easy usage (primarily meant for the HA integration).

Using the high level 'Devices' interface

An example on how to read the most interesting registers from the inverter:

import asyncio

from huawei_solar import (
    SUN2000Device,
    create_device_instance,
    create_tcp_client,
)
from huawei_solar import register_names as rn

async def test() -> None:
    """Run test."""
    client = create_tcp_client(host="192.168.1.1", port=503)
    device = await create_device_instance(client)

    assert isinstance(device, SUN2000Device)
    print(
        await device.batch_update(
            [
              rn.INPUT_POWER,
              rn.LINE_VOLTAGE_A_B,
              rn.LINE_VOLTAGE_B_C,
              rn.LINE_VOLTAGE_C_A,
            ]
        ),
    )

if __name__ == "__main__":
    asyncio.run(main())

This results in the following output being printed:

{'input_power': Result(value=82, unit='W'), 'line_voltage_A_B': Result(value=233.4, unit='V'), 'line_voltage_B_C': Result(value=0.0, unit='V'), 'line_voltage_C_A': Result(value=0.0, unit='V')}

Frequently asked questions

Q: the connection is interrupted a few seconds after connecting to the Huawei Device. How do I solve this?

A:: Huawei devices only support one connection at a time. If your connection is interrupted, this is typically because another device is trying to (re-)connect to it. Disable that device and try again.

Acknowledgements

The initial implementation of v1 was done by @Emilv2.

Subsequent development on v2 was done by @wlcrs.