Development Of Multi-Point Multi-Wavelength High Temperature Measurement System

Temperature measurement is widely used in aerospace,defense military,industry,materials,energy metallurgy and soon.Accurate real-time measurement of temperature has an important impact on the development of various industries.This subject has developed a multi-point multi-wavelength high-temperature measurement system with temperature measurement range of 1300K-2300 K for the requirements of the project.It applies multi-spectral radiation temperature measurement technology to achieve real-time measurement of temperature information of multiple target points.This paper is mainly composed of three parts: hardware circuit construction,program debugging preparation,instrument calibration and test experiment.The optical system is designed with aiming and focusing function,the radiation energy received by three target points is transmitted to the photodetector array by optical fiber splitting,and the energy information of six channels under different target points is received by 18 silicon photodiodes,the detector array is connected with 18 independent signal processing circuits.The AD820 is used to construct an IV conversion circuit to convert optical information into an easily collectable electrical signal.A first-order passive and second-order active combination filter circuit is build by OP07 to ensure the stability of the circuit while completing the power compensation.OP07 is also employed to build a two-stage amplifier circuit,the former signal processing data are used when the latter signal is saturated,this method can improve the signal-to-noise ratio as much as possible without exceeding the measurement range.Finally,the USB5630 data acquisition card is applied to collect the two-stage amplification signals of each channel under different targets.A total of 36 channels need to be collected at the same time to realize the information exchange between the hardware circuit and the host computer.The software part makes use of Visual Stdio as the development environment,and the C# language completes the software writing.The program mainly consists of three aspects: calibration process,signal acquisition and data processing.In the calibration process,the data are collected several times and processed by means of de-extremum,and it applies the Access database to complete the calibration test data storage;The signal acquisition transmits the data to the host computer and operates the txt file to store the data,which facilitates the subsequent data processing;The data processing adopts the calibration fitting parameters to calculate the bright temperature values under different channels of each target,and employs the secondary measurement method to calculate the true temperature and the emissivity measurement of each channel at different times.The temperature calibration test and accuracy test of the black body furnace has been completed after the platform is built,,and the repeatability and stability test of the experiment has also been completed by using the tungsten filament lamp.After calculation and analysis,the overall uncertainty of the instrument is less than 3%,and the experimental results fully meet the project requirements.