Temperature Influence Correction of a NDIR Carbon Dioxide Sensor

摘要

For an adequately controlled indoor air quality in intelligent buildings a measurement of CO_2 concentration is the most important prerequisite. Nevertheless, most CO_2 sensors available at present do not fulfill low-cost and long-term stability criteria, which are important for the choice of sensors in this application field. A novel optical NDIR CO_2 sensor system for the range of 0-2000 ppm is presented, which has been developed especially for use in private buildings. The main part of signal pre-processing is carried out by means of a digital board. A special investigation was dedicated to the possibilities of digital correction of temperature influence of the sensor signal in order to reduce measurement errors. The sensor signal is described by a model based on the Lambert-Beer law and including temperature influence correction. The total errors after temperature compensation were minimized to 2,5% and correspond to a concentration measurement error of approx. 50 ppm.