Esphome Huawei Modbus Register 37118: Huawei meter grid frequency

Technical Definition

The register Huawei meter grid frequency at address 37118 is used to monitor huawei meter grid frequency on the Esphome Huawei.

• Protocol: Modbus RTU
• Data Type: S WORD
• Unit: Hz
• 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 grid frequency (Address: 37118)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=37118, 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 grid frequency"
  address: 37118
  value_type: S_WORD
  unit_of_measurement: "Hz"

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: Frequency of the AC grid (Hz). Typically 50Hz or 60Hz depending on region.

Troubleshooting: Out-of-range or zero suggests grid instability or meter malfunction. Check grid quality.