Relative Humidity, Temperature, Barometric Pressure, and CO2-percentage in Air Probe – SDI-12, Modbus/RS-485, or NMEA-0183 over RS422

In stock (can be backordered)


  • Stainless steel enclosure and filter cap, engineered to shield sensing elements in harsh environments
  • Waterproof protection of internal electronics—only sensor elements are exposed
  • UV-protected and oil-resistant flexible cable
  • Low-power consumption suitable for battery-powered applications
  • Electrical interfaces: SDI-12 (SDI-12 protocol v.1.4), RS-485 (Modbus protocol), UART (Modbus protocol), NMEA-0183 over RS422, USB


The Evvos RHTP probe combines meteorological grade sensors for air temperature, relative humidity, and barometric pressure measurements. It is designed to provide high-quality environmental data, real-time measurements, and calculation of multiple derivative parameters. The RHTPCO2 version of the probe includes an additional measurement of CO2-percentage (in air) compensated for relative humidity and air temperature.
It is compatible with OneSense Pulse and Voltage and OneSense Environment and Agriculture as well as many other telemetry transmitters or dataloggers supporting SDI-12, Modbus/RS-485, or NMEA 0183 interface.

Primary parameters

  • Relative humidity
  • Air temperature
  • Barometric pressure
  • CO2-percentage in air

Typical Applications

  • Environmental monitoring
  • Weather forecasting solutions
  • Industrial data acquisition
  • Precision agriculture/farming
  • Cold chain and HVAC applications
  • Internet of Things (IoT)

Secondary parameters

  • Absolute humidity
  • Dew point
  • Wet-bulb temperature
  • Vapour pressure
  • Saturated vapour pressure
  • Atmospheric pressure at sea level
  • Heat index
  • Mixing ratio
  • Specific enthalpy
  • Boiling point of water
  • Speed of sound in air
  • Water activity in air

Additional information

Weight0.152 kg

18 x 155 mm


A 1.5 m. (5,9ft), 5-position (SDI-12) or 4-position (Modbus/RS-485, or NMEA-0183), PUR halogen-free, black-gray RAL 7021, free cable end, on socket straight or angled M-12, A-coded sensor cable. Custom cable length on request.


User's Manual

SDI-12 –
Modbus/RS-485 –
NMEA 0183 Interface TALKER rev.1.0 –

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