CO2 sensors ensure long-term stability and maintenance-free operation

The IMG-CB Series of accurate, highly stable CO2 sensors aimed at gas detection applications in the agricultural and building energy management system (BEMS) markets, have been introduced by Murata. Murata’s high performance CO2 sensors are based on non-dispersive infrared sensor (NDIR) technology, which is now the most popular type of sensor technology used in CO2 measurement.

Murata’s proprietary implementation of NDIR enables accurate calibration regardless of any degradation that may occur over time in the IR light source, optical path or IR sensor, thus ensuring long term stability and enabling many years of maintenance-free operation in critical applications.

For many customers it is important to maintain initial CO2 sensor accuracy in order to sustain high levels of energy savings in building climate control. Eliminating yearly, manual calibration costs means Murata’s CO2 sensors can actually reduce the total cost overall. Other methods of CO2 detection, which are used in home appliances and IoT air quality applications, reportedly do not offer high enough levels of accuracy and stability for use in more demanding, critical applications.

Specific applications for the IMG-CB Series include BEMS, where ventilation control is often required to keep the concentration of CO2 below defined levels, and in agricultural applications such as greenhouses, where the successful promotion of photosynthesis is achieved through CO2 concentration control.

The principle of operation of Murata’s NDIR sensor involves focusing an IR light source to create an optical beam that passes through any gases present, including CO2. After passing through an optical band pass filter, an IR sensor then measures the level of IR light present, which indicates the CO2 levels in the optical path.

Murata’s CO2 sensor is available in three forms, as a module measuring 67x92x20mm (IMG-CA0011-01<0-2,000ppm>, IMG-CA0012-01<0-3,000ppm>), as a packaged sensor for agricultural applications measuring 80 x 125 32 mm (IMG-CA**), and in a cased package for BEMS applications (IMG-CB**), with a sampling probe already attached. In all cases the output is a 0 to 5 V analogue signal.

The sensors are able to perform over a wide operating temperature range from zero to 50°C and offer a measurement range of zero to 3,000ppm with an accuracy of +/- 50ppm + five percent of reading, typically +/- 30ppm + 2.5% of reading. Power requirement is AC/DC 24V, or DC 12V, and power consumption is an average of 0.5, 2.0W maximum. The sensor’s measurement interval is five seconds.