Esphome Huawei Modbus Register 37121: Huawei meter imported energy

Technical Definition

The register Huawei meter imported energy at address 37121 is used to monitor huawei meter imported energy on the Esphome Huawei.

• Protocol: Modbus RTU
• Data Type: S DWORD
• Unit: kWh
• Access: Read Only

How to Read (Python pymodbus)

Use this code snippet to read this specific value via RS485:

from pymodbus.client.sync import ModbusSerialClient

client = ModbusSerialClient(method='rtu', port='/dev/ttyUSB0', baudrate=9600)
client.connect()

# Read Huawei meter imported energy (Address: 37121)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=37121, count=2, unit=1)

if not result.isError():
    print(f"Raw Value: {result.registers}")
else:
    print("Error reading register")

client.close()

Integration (Home Assistant)

Paste this into your configuration.yaml:

- platform: modbus_controller
  name: "Huawei meter imported energy"
  address: 37121
  value_type: S_DWORD
  unit_of_measurement: "kWh"

Connection Diagram

Here is the standard RS485 wiring for this configuration:

graph TD
    PLC[Host Controller / Home Assistant]
    Device[Esphome Huawei]

    PLC -- "A+ (D+)" --> Device
    PLC -- "B- (D-)" --> Device
    PLC -- GND --> Device

💡 Engineer's Insight

Analysis: Energy imported from the grid by the load (kWh). Tracks power drawn from utility.

Troubleshooting: Zero means no import. Verify sufficient solar generation or inverter standby.