Development Of Electronic System Of Non-contact Infrared Radiation Thermometer

Infrared temperature measurement technology has the advantages of non-contact,fast,accurate,and high sensitivity,and is widely used in aviation,aerospace,navigation,scientific research,and industry.At present,the laboratory calibration of infrared thermometers is mostly realized by multi-point temperature measurement in a constant temperature room,which requires high manpower and material resources and a long measurement period.In order to reduce the cost and cycle of laboratory calibration,this paper develops the electronic system of non-contact infrared radiation thermometer,and proposes a wide temperature compensation and calibration algorithm.According to the design requirements and working principle of the infrared thermometer,this paper develops the embedded control system based on the STC8 A singlechip microcomputer.Two sets of power supply systems,220 V and lithium battery,are designed to provide guarantee for the measurement of the instrument in outdoor places.The working band range of the instrument is 9.6～12.5μm,and the DC motor of the chopper is driven by the main control chip to perform chopping,so as to realize the collection of the target radiation signal by the pyroelectric detector PY2214.At the same time,the photoelectric tube is used to measure the chopping frequency and phase,and the measured value provides the basis for judging the positive and negative temperature of the target and data processing.In order to eliminate the influence of environmental factors on the measurement results,a high-precision PT100 platinum resistance thermometer is used to collect the internal radiation temperature.The collected data can remove the interference of noise signals through algorithms and provide data support for the calibration model.The LCD touch screen module design is added for the visual observation of the measurement data of the lower computer and the user’s human-computer interaction operation.At the same time,the MAX232 communication module realizes data transmission with the host computer,in which the collected data is algorithmically inverted on the host computer,and the inverted data is displayed in real time on the page in the form of text and curves.The upper computer is equipped with a storage function for data backup.After the design of the electronic system of the infrared thermometer is completed,the normal operation of each functional module is verified through experiments,and the index verification is carried out,all of which meet the design requirements.Using three standard cavity blackbodies for absolute radiation calibration,the study of wide temperature compensation algorithm for uncooled infrared thermometers is realized.Through scanning temperature measurement and reference temperature measurement,the change relationship between ambient temperature,black body temperature and measured value is obtained,and the calibration of wide temperature and adaptive ambient temperature is realized at low cost.Considering various factors that cause the maximum uncertainty of calibration,the analysis results show that the maximum uncertainty at-50～0°C is 1.44°C,the maximum uncertainty at 0～200°C is 0.86°C,and the maximum uncertainty at 200～300°C is 0.56℃.And it can adaptively measure within the ambient temperature of 23±5°C,which meets the requirements of the design index of the infrared thermometer.