EmsTechLabs Logo EmsTechLabs

.Tongdy Tg9 Modbus Register 8: TG9 CO₂ Concentratie

Technical documentation for Modbus register 8 on .Tongdy Tg9. Data type: U WORD. Includes Python and YAML configuration examples.

January 16, 2026 3 read

Technical Definition

The register TG9 CO₂ Concentratie at address 8 is used to monitor tg9 co₂ concentratie on the .Tongdy Tg9.

  • Protocol: Modbus RTU
  • Data Type: U WORD
  • Unit: ppm
  • 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 TG9 CO₂ Concentratie (Address: 8)
# Note: Check if your device uses 0-based or 1-based addressing
result = client.read_input_registers(address=8, 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: "TG9 CO₂ Concentratie"
  address: 8
  value_type: U_WORD
  unit_of_measurement: "ppm"

Connection Diagram

Here is the standard RS485 wiring for this configuration:

graph TD
    PLC[Host Controller / Home Assistant]
    Device[.Tongdy Tg9]

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


💡 Engineer's Insight

Analysis: CO₂ Concentration (ppm). Measures the level of carbon dioxide in the air.

Troubleshooting: Sensor issue, poor ventilation, or abnormal CO₂ source. Verify sensor function and ventilation system.