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Digital Control Systems

6475 SW Fallbrook Place Beaverton, OR 97008 USA

Toll Free: 1-877-468-6337

Phone: (503)246-8110

Fax: (503) 246-6747 


AirSense Model 305


PDF Logo Model 305e Manual

PDF Logo Model 305e Brochure

The Cost-Effective Way to Integrate Infrared CO2 Sensing Into Your Product

The AirSense™ Model 305e is the first commercially-available non-dispersive infrared (NDIR) CO2 concentration measurement subsystem designed for the OEM market: it provides equipment manufacturers the ability to integrate IR CO2 sensing capability into a wide range of products. Specifically designed for embedded applications, the microprocessor-based AirSense™ Model 305e is the easiest and most cost-effective way to add CO2 measurement to your product line.

    Until now, the only way to include CO2 measurement capabilities in a product was to purchase a completely freestanding unit (often designed for an unrelated application) and then design around it. With the AirSense™ Model 305e, developers can easily design the CO2 sensing functionality directly into their electronics, rather than tacking it on as an accessory. The AirSense™ Model 305e’s single small circuit board is just another component easily integrated into your product.

    The DCS Model 305e is a complete, low power OEM module for measuring CO2 levels. The compact module includes the non-dispersive infrared (NDIR) sensing cell as well as all the required support electronics. Its low power consumption, compact footprint, and flexible interfacing modes make the Model 305e easy to design-in, and its modern self-referencing measurement system provides many years of trouble-free service.

    The AirSense™ Model 305e is easy to use: the linear measurement output is available as an analog voltage or a pulse-width modulated digital signal. Calibration can be easily performed with the jumpers and buttons on the module through logic inputs driven by the host electronics, or directly from operator-actuated switches. An optional four-digit LED display module can be connected to the digital interface to report CO2 concentration. The minimal energy consumption makes it ideal for battery or other low-power applications, and the sensing cell can be configured for diffusion or sample draw requirements.




Measurement method

Non-dispersive infrared (NDIR)

Measurement range

0 - 2000 ppm CO2

Measurement resolution

10 ppm

Measurement accuracy

±5% of reading or ±100 ppm

Analog measurement output

0.1 - 3 VDC

Digital measurement output

5 volt PWM; duty cycle varies from 10% to 90%

Digital interface

Bi-directional SPI

Operating power requirements

4.75 to 5.25 VDC @ .05 Amps (average)

Operating temperature range

10 to 50° C.

Operating humidity range

0 to 95% RH (non-condensing)


Single gas


2.1” x 2.2 footprint, .81” tall





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Download a complete, practical plan to improve the air quality in schools.

Improve IAQ, While Saving Energy.
The use of CO2 sensors can save more than $1 per square foot of energy cost annually.