Research And Implementation Of Spectral Absorption CO₂ Gas Concentration Measuring Device

The CO₂ concentration measuring device based on tunable laser diode has the problems of high cost and high power consumption.In order to measure the concentration of CO2 gas conveniently,a CO2 gas concentration measuring device based on spectral absorption is designed.In paper,the principle of spectral absorption CO₂ gas concentration measurement and non-spectral infrared technology are expounded,the hardware circuits and software programs of the CO₂ gas concentration measuring device based on spectral absorption are designed,and the measurement and display of CO₂ gas concentration are realized.The hardware circuits include power supply circuit,light source modulation circuit,signal conditioning circuit,temperature measurement circuit,A/D conversion circuit,external storage circuit,RTC circuit and serial communication circuit.And software programs include PC program and single-chip program.And by MySQL database used,the measurement data is saved completely,which provides convenience for future data research and analysis.In the aspect of data processing and analysis,the calibration of CO₂ gas concentration measuring device is carried out by using standard concentration of CO₂ gas,and the data fitting of the measuring device is completed by using Origin software.In view of the disturbance caused by temperature,the radial basis function neural network is used to compensate the temperature effect of the spectral absorption CO₂ concentration measuring device.Experiments show that the maximum error of the measuring device is 4.76%after temperature compensation.