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Han C6 B5 Modbus Register 123: Power Factor

Technical documentation for Modbus register 123 on Han C6 B5. Data type: U WORD. Includes Python and YAML configuration examples.

January 16, 2026 3 read

Technical Definition

The register Power Factor at address 123 is used to monitor power factor on the Han C6 B5.

  • Protocol: Modbus RTU
  • Data Type: U WORD
  • Unit:
  • 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 Power Factor (Address: 123)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=123, 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: "Power Factor"
  address: 123
  value_type: U_WORD
  unit_of_measurement: ""

Connection Diagram

Here is the standard RS485 wiring for this configuration:

graph TD
    PLC[Host Controller / Home Assistant]
    Device[Han C6 B5]

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


💡 Engineer's Insight

Analysis: Ratio of real power to apparent power for the system. Unitless (0-1).

Troubleshooting: Zero indicates a purely reactive load or fault. Check load type and connection integrity.