Modbus Ozone2 Modbus Register 0: Device gas

Technical Definition

The register device gas at address 0 is used to monitor device gas on the Modbus Ozone2.

• Protocol: Modbus RTU
• Data Type: FP32 R
• Unit:
• 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 device gas (Address: 0)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=0, 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: "device gas"
  address: 0
  value_type: FP32_R
  unit_of_measurement: ""

Connection Diagram

Here is the standard RS485 wiring for this configuration:

graph TD
    PLC[Host Controller / Home Assistant]
    Device[Modbus Ozone2]

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

💡 Engineer's Insight

Analysis: Ozone gas concentration level. Units are typically ppm or ppb.

Troubleshooting: Sensor malfunction, calibration drift, or no ozone generation. Check ozone source and sensor health.