Measurement of gas concentration by measuring the absorption ratio using two detector elements
NDIR (Non-Dispersive Infrared) CO2 sensors are generally classified into three types: Single light source, single wavelength type, Dual light source, dual wavelength type, and Single light source, dual wavelength type sensor.
The "single light source, dual wavelength technology” adopted by the CDM7162 is equipped with two types of optical filters. By measuring intensities of the infrared lights that have passed through each filter, CO2 concentration is measured accurately.
The CDM7162 has two different optical filters in front of each detector. One detector measures transmitted infrared light intensities in the infrared wavelength range that is absorbed by CO2 (CO2 absorption wavelength), and the other detector measures transmitted infrared light intensities in the wavelength range that is not absorbed by CO2 (reference wavelength). CO2 concentration is calculated from the difference between transmitted light intensities at the CO2 absorption wavelength and the reference wavelength, resulting in accurate measurement of CO2 concentrations.
| System | Single light source, single wavelength sensor |
|---|---|
| Design | Measures a single wavelength from a single light source |
| Structure |  |
| System | Single light source, dual wavelength sensor |
|---|---|
| Design | Measures two wavelengths split from a single light source |
| Structure |  |
～No calibration required with Figaro’s proprietary signal processing technology ～
The CDM7162 is featured with software baseline corrections that use as a reference CO2 concentration in outdoor air or in an unoccupied indoor environment which is equivalent to outdoor air. When the sensor is used in an environment where it is periodically exposed to the CO2 concentration which is similar or equivalent to the outside air (approximately 400ppm), accurate and stable CO2 concentration measurements are performed over a long time without frequent calibration.
Compact size with thickness of only 8 mm fits in well with low-profile environmental monitors or controllers.
Measured CO2 concentration data can be output to a PC or external control device via UART (Universal Asynchronous Receiver Transmitter) interface, which is embedded into most of the latest microprocessors.
The CDM7162 also incorporates an I2C (Inter-Integrated Circuit) interface for high-speed communications between the CO2 sensor and peripheral devices that are directly connected within a short distance. The I2C interface is not suitable for communication with remote devices. By connecting the CO2 sensor with an external microprocessor via the UART interface, measured data can be sent to or be received from a variety of control devices and equipment through the microprocessor. By utilizing a microcomputer with communication functions, CO2 concentration data can be transmitted wirelessly for remote control operations.
Customer and Technical Support
Based on the in-depth knowledge and expertise that Figaro has acquired through its 50+ years of experience in supplying high quality gas sensing solutions to global markets, Figaro provides sound and responsive technical support for application circuit design, selection of electronic components, detector housing design, gas detector manufacturing process, and other customer-specific technical questions.
Content-rich Technical Documents
Individual product data sheets, detailed technical information and application notes are available for customer’s reference.
Suitable for a wide range of applications such as ventilation control equipment, air conditioning equipment, and small measuring devices for indoor environmental comfort and energy efficiency. Expected application includes input devices for environmental measurement in IoT and M2M products.
Made in Japan.
All CO2 sensors are factory calibrated to standard CO2 gas in a computer-controlled automatic calibration system. Stringent quality control processes at Figaro ensure high reliability of its gas sensors.
Figaro has a wide range of product lines, including semiconductor VOC sensors for detection of low concentrations and battery operable electrochemical CO sensors. Figaro is one of the few gas sensor manufacturers in the world supplying VOC, CO, and CO2 gas sensors.