Thd Voltage Line Modbus Register 30339: Entities name prefix - slave entities prefix name - THD Voltage Line (L3L1)

Technical Definition

The register entities name prefix - slave entities prefix name - THD Voltage Line (L3L1) at address 30339 is used to monitor entities name prefix - slave entities prefix name - thd voltage line (l3l1) on the Thd Voltage Line.

• Protocol: Modbus RTU
• Data Type: U DWORD
• 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 entities_name_prefix - slave_entities_prefix_name - THD Voltage Line (L3L1) (Address: 30339)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=30339, 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: "entities_name_prefix - slave_entities_prefix_name - THD Voltage Line (L3L1)"
  address: 30339
  value_type: U_DWORD
  unit_of_measurement: "%"

Connection Diagram

Here is the standard RS485 wiring for this configuration:

graph TD
    PLC[Host Controller / Home Assistant]
    Device[Thd Voltage Line]

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

💡 Engineer's Insight

Analysis: Total Harmonic Distortion of Line Voltage L3-L1 (%). Typical values are below 5%.

Troubleshooting: High values may indicate poor power quality, faulty loads, or transformer issues. Check for electrical noise or grounding problems.