MODBUS CO2 and Pressure Sensor TSM400-4-CP

Carbon Dioxide Sensors | Modbus | TSM400-4-CP

CO2, or Carbon dioxide, is a colorless and odorless gas, constituting the fourth most abundant component in the Earth's atmosphere. Monitoring its concentration, especially indoors, is vital for maintaining a healthy and efficient environment.

TSM400-4-CP is a versatile sensor supporting the MODBUS RTU protocol via an RS-485 interface. This sensor is designed to measure barometric pressure and CO2 concentration.

The MODBUS device incorporates an advanced non-dispersive infrared sensing element (NDIR) for precise CO2 measurements. NDIR is the prevailing technology for accurately measuring CO2 concentration, relying on the absorption of specific wavelengths of infrared (IR) light by CO2 molecules.

The CO2 sensing element includes built-in humidity and temperature sensors, enhancing measurement accuracy.

For carbon dioxide measurements, self-calibration is available. This process occurs when the sensor is exposed to fresh air with an approximate CO2 concentration of 400 ppm.

The barometric pressure sensor comes factory-calibrated and maintains accuracy without requiring lifetime recalibration.

The TSH400-4-CP sensor is encased in a slim plastic enclosure, with the lower part designed for easy installation on standard flush-mounted or cavity wall boxes with a maximum installation opening of 61 mm.


  • LED indicator for communication status
  • Long-term stability achieved through digital signal processing
  • Self-calibration for CO2 measurements in fresh air
  • Customizable communication parameters
  • Non-volatile memory for storing settings
  • Firmware updates via the interface


  • Indoor air quality (IAQ) monitoring
  • Monitoring for CO2 leakage in storage facilities
  • Smart ventilation system control
  • CO2 level monitoring in restaurants and breweries

The MODBUS CO2 and pressure sensor is compatible with:

  • 4G LTE universal IO module TCG140-4
  • Energy monitoring module TCW260
  • GSM-GPRS remote IO module TCG140
  • Third-party controllers

Technical Properties:

  • Physical characteristics
  • Dimensions: 81 x 81 x 30mm
  • Weight: 66g
  • Environmental limits
  • Operating temperature range: -20 to 60°C
  • Operating relative humidity range: 5 to 95% (non-condensing)
  • Storage temperature range: -20 to 60°C
  • Storage relative humidity range: 5 to 95% (non-condensing)
  • Ingress protection: IP20
  • Power requirements
  • Operating voltage range (including -15/+20% according to IEC 62368-1): 4.5 to 26VDC
  • Current consumption: 25mA@5VDC (Peak: 150mA@5VDC)
  • CO2 measurements
  • Range: 400 to 5000ppm
  • Accuracy: ± (40ppm + 5%)
  • Resolution: 1ppm
  • Calibration: Manual/Automatic
  • Pressure measurements
  • Range: 10 to 1200hPa
  • Accuracy (min): ±1.5% (25°C, 750hPa)
  • Accuracy (max): ±2.5% (-20°C to + 85°C, 300 to 1100hPa)
  • Resolution: 1hPa
  • Interface
  • Response time ≤ 50ms
  • Master response time-out ≥ Response time + Answer time
  • The answer time depends on the number of bits and the baud rate
  • Warranty
  • Warranty period: 3 years