Temperature-Humidity-CO2 Monitor with Output Relay

ITEM # CDM77232

Temperature-Humidity-CO2 Monitor with Output Relay

The #CDM77232 temperature-humidity-CO2 monitor is ideal for monitoring the indoor air quality (IAQ) of houses, offices, classrooms, factories, hospitals and hotels. It includes a relay for activating a ventilation system.


Best For:



  • Measures ambient temperature, relative humidity (RH), dew point and wet bulb temperatures, and CO2 level
  • The backlit LCD displays ambient temperature, RH and CO2 level on separate readouts
  • Uses a stable, non-dispersive infrared (NDIR) sensor to measure CO2
  • Calculates, periodically updates and displays an 8-hr. time-weighted average (TWA) of CO2 exposure and a 15-minute short-term exposure limit (STEL)
  • Adjustable Hi and Lo audible/visual CO2 alarm levels
  • The output relay activates/cancels its signal when the CO2 level exceeds the preset Hi alarm level or falls below the preset Lo alarm level
  • Min/Max memory + data hold
  • Optional #ASFTKIT PC data logging software/hardware is available
  • 33% and 75% #HR33 and HR75 reference salts are available to calibrate RH measurement in the field
  • Auto power off (can be disabled for data logging and calibration)
  • Wall or desktop mount
  • Specifications


    • Ambient temperature measurement range/resolution: 14° to 140°F (-10° to 60°C)/0.1°
    • Ambient temperature measurement accuracy: ±0.9°F (±0.6°C)
    • RH measurement range/resolution: 0 to 99.9%RH/0.1%
    • RH measurement accuracy: ±3% from 10 to 90%RH; ±5% elsewhere
    • CO2 measurement range/resolution: 0 to 5000ppm/1 ppm
    • CO2 measurement accuracy: ±(30 ppm + 5% of reading)
    • CO2 calibration level: 400ppm
    • CO2 alarm level adjustment range: 100 to 9900 ppm
    • CO2 alarm relay outputs: 5V (activated); 0V (cancelled)
    • Warmup time: 30 seconds
    • Response times: 30 seconds for temperature and CO2; 30 minutes for RH
    • Auto power off: After 20 minutes of inactivity
    • Operating temperature: 32° to 122°F (0° to 50°C) @ <80% RH
    • Weight: 14 oz. (397g)
    • Power source: #Z110VADPT adaptor (included)


    • #Z110VADPT adaptor 
    • 1-year limited warranty


    • 6.88 x 5.63 x 2.38 in. (174.75 x 143 x 60.45mm)