Duct Carbon Dioxide (CO2) transmitters - CDD 24-series

Duct CO2 transmitter CDD 24S

The duct CO2 transmitter CDD 24 is a duct CO2 transmitter series designed to be installed in HVAC return air ducts.

The CO2 sensing element uses the Non-Dispersive Infrared Technology (NDIR) with the patented self-calibration system to guarantee the long term stability and up to 15 years life time.

The duct Carbon Dioxide transmitter CDD 24 duct probe transmitter offers temperature and humidity option.

The high accuracy temperature and humidity combined sensor provide a digital interface and outstanding full range linearity.

The one or three analog 0-10 Vdc or 4-20mA outputs are selectable by jumpers. Modbus RS485 communication interface is provided.

Optional LCD can display all measurements and is usable easily in more applications.

Unique 3-color backlit LCD provides more clear indication and an alarm function.

The duct CO2 transmitter CDD 24 offers simplicity in design and installation with special the take-down filter to avoid pollution and influence of measurement.

The duct Carbon Dioxide transmitter CDD 24 have fifteen years lifetime, calibrate themselves to local background levels

  • Selectable output 0-10 Vdc or 4-20 mA
  • Modbus RS485 communication interface
  • Measures 0-2.000 ppm
  • Power supply 24 Vac/dc
  • Accuracy +/-40 ppm + 2% reading @ 25°C


      • 4 different models:

    • CDD 24S:

      • duct CO2 transmitter, standard version.

    • CDD 24HT:

      • same as standard version and with Humidity and Temperature outputs.

    • CDD 24L:

      • same as standard version and with LCD display

    • CDD 24HTL:

      • same as standard version and with Humidity and Temperature outputs and with LCD display.


    Download datasheets

    Duct Carbon Dioxide (CO2) Transmitters - CDD 24-series.pdf


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