CM1109 Dual IR Source NDIR CO2 Sensor

The CM1109 is designed to measure high concentrations of CO2 (up to 5% volume in air) for safety alarm applications in brewery agricultural industrial and cold chain storage applications.
The sensor is an ideal for indoor ventilation control and CO2 monitoring in commercial and residential HVAC applications.


  • High Accuracy Supports WELL, RESET, ASHRAE 62.1-2019 Addendum aa & California Title 24 Applications
  • Long Lifespan 15+ years
  • Maintenance Free - Automatic Baseline Calibration (ABC)
  • Temperature and Humidity Compensation Throughout The Entire Measurement Range
  • Superior Stability & Accuracy



Accuracy ‘0% to 0.2% volume +/-0.02%
Resolution ‘0.001% volume in air
Measurement Range 0% to 5% CO2 volume in air
Temperature Range 14˚F to 155˚F (-10˚C to 50˚C)
Humidity Range 0-95% RH
Supply Voltage 4.5-5.5 VDC
Supply Current <50mA
Communication Interfaces UART & I2C
Dimensions 33.5 x 22 x 13.1mm
Weight 7g
Life Expectancy >10 years

Operating Principle

Dual Source Non-Dispersive Infrared (NDIR) Sensors

NDIR sensors leverage Lambert-Beer’s law that states certain gasses exhibit absorption characteristics at a specific infrared wavelength.

Dual IR Source NDIR sensors use an two infrared light sources and a single IR detectors that is “tuned” to the specific wavelength for the target gas. The IR light source #1 is passed through an optical bench that “folds” the light within the optical bench to create a long optical path length – providing high accuracy and resolution when measuring the target gas. The IR light source #2 has a very short optical path length and can be used as a reference to overall light intensity of both light sources.

As the target gas concentration increases, the amount of received IR light at the IR detector decreases, this relationship is converted to a PPM measurement within the sensor.


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