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Net Active Energy Modbus Register 30397: Entities name prefix - slave entities prefix name - Net Active Energy Total

Technical documentation for Modbus register 30397 on Net Active Energy. Data type: U DWORD. Includes Python and YAML configuration examples.

January 16, 2026 3 read

Technical Definition

The register entities name prefix - slave entities prefix name - Net Active Energy Total at address 30397 is used to monitor entities name prefix - slave entities prefix name - net active energy total on the Net Active Energy.

  • Protocol: Modbus RTU
  • Data Type: U 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 entities_name_prefix - slave_entities_prefix_name - Net Active Energy Total (Address: 30397)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=30397, 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 - Net Active Energy Total"
  address: 30397
  value_type: U_DWORD
  unit_of_measurement: "kWh"

Connection Diagram

Here is the standard RS485 wiring for this configuration:

graph TD
    PLC[Host Controller / Home Assistant]
    Device[Net Active Energy]

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


💡 Engineer's Insight

Analysis: Net Active Energy Total: Cumulative electrical energy consumed or produced. Units: Kilowatt-hours (kWh) or Megawatt-hours (MWh).

Troubleshooting: Zero could mean no energy flow recorded, a meter malfunction, or a reset of the energy counter.