Em340 Modbus Register 24: Dev kVA L1

Technical Definition

The register dev kVA L1 at address 24 is used to monitor dev kva l1 on the Em340.

• Protocol: Modbus RTU
• Data Type: S DWORD R
• Unit: VA
• 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 kVA L1 (Address: 24)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=24, 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 kVA L1"
  address: 24
  value_type: S_DWORD_R
  unit_of_measurement: "VA"

Connection Diagram

Here is the standard RS485 wiring for this configuration:

graph TD
    PLC[Host Controller / Home Assistant]
    Device[Em340]

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

💡 Engineer's Insight

Analysis: Apparent power (kVA) on Phase L1. Total power delivered to the load, including reactive.

Troubleshooting: Zero indicates no load or communication issue. Check L1 load integrity and device connectivity.