Dev S3 Eb3 Modbus Register 120: Dev Active Power L3 Export

Technical Definition

The register dev Active Power L3 Export at address 120 is used to monitor dev active power l3 export on the Dev S3 Eb3.

• Protocol: Modbus RTU
• Data Type: U DWORD
• Unit: W
• 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 dev Active Power L3 Export (Address: 120)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=120, 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: "dev Active Power L3 Export"
  address: 120
  value_type: U_DWORD
  unit_of_measurement: "W"

Connection Diagram

Here is the standard RS485 wiring for this configuration:

graph TD
    PLC[Host Controller / Home Assistant]
    Device[Dev S3 Eb3]

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

💡 Engineer's Insight

Analysis: Active power exported from Phase L3. Units: Watts (W). Indicates power flow out of the system.

Troubleshooting: Verify export settings, grid connection, and L3 current direction. Potential issue with generation or load shedding.