Em340 Package Modbus Register 42: modbus controller name sys kVA

Technical Definition

The register modbus controller name sys kVA at address 42 is used to monitor modbus controller name sys kva on the Em340 Package.

• 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 modbus_controller_name sys kVA (Address: 42)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=42, 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: "modbus_controller_name sys kVA"
  address: 42
  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 Package]

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

💡 Engineer's Insight

Analysis: System apparent power (kVA). Represents the total power flow in the circuit, including real and reactive power.

Troubleshooting: Zero typically means no load connected or a complete system measurement failure.