Schundmeter Modbus Register 381: Chint power factor phase 2

Technical Definition

The register chint power factor phase 2 at address 381 is used to monitor chint power factor phase 2 on the Schundmeter.

• Protocol: Modbus RTU
• Data Type: S WORD
• Unit: cosphi
• 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 chint power factor phase 2 (Address: 381)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=381, 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: "chint power factor phase 2"
  address: 381
  value_type: S_WORD
  unit_of_measurement: "cosphi"

Connection Diagram

Here is the standard RS485 wiring for this configuration:

graph TD
    PLC[Host Controller / Home Assistant]
    Device[Schundmeter]

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

💡 Engineer's Insight

Analysis: Power Factor Phase 2 (PF2). Unitless value representing the ratio of real power to apparent power in phase 2.

Troubleshooting: Zero if no load or severe phase imbalance. Could indicate a faulty meter or connection.