Heidelberg wb example Modbus Register 7: L2 A rms

Technical Definition

The register L2 A rms at address 7 is used to monitor l2 a rms on the heidelberg wb example.

• Protocol: Modbus RTU
• Data Type: U WORD
• Unit: A rms
• 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 L2 A rms (Address: 7)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=7, 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: "L2 A rms"
  address: 7
  value_type: U_WORD
  unit_of_measurement: "A rms"

Connection Diagram

Here is the standard RS485 wiring for this configuration:

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

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

💡 Engineer's Insight

Analysis: Phase L2 RMS current in Amperes (A). Measures effective current flow in the second phase.

Troubleshooting: Zero value may indicate no load, blown fuse, or wiring issue on L2. Check connections and load status.