Development and Test of On-Line Spectroscopic System Based on Thermostatic Control Using STM32 Single-Chip Microcomputer
HUANG Chao1, 2, ZHAO Yu-hong1, ZHANG Hong-ming2*, LÜ Bo2, 3, YIN Xiang-hui1, SHEN Yong-cai4, 5, FU Jia2, LI Jian-kang2, 6
1. School of Electrical Engineering, University of South China, Hengyang 421001，China
2. Institute of Plasma Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, China
3. Science Island Branch Graduate School，University of Science and Technology of China, Hefei 230031, China
4. School of Physics and Materials Engineering, Hefei Normal University, Hefei 230601, China
5. Institute of Energy, Hefei Comprehensive National Science Center, Hefei 230031, China
6. School of Nuclear Science and Technology, University of South China, Hengyang 421001，China
Abstract：Near-Infrared (NIR, wavelength range: 780~2 500 nm) on-line spectral analysis technique has the advantages of miniaturization, rapid detection, and stable and reliable results. Therefore, this technique is widely used in the field of industrial detection. Because the spectroscopic system is significantly affected by ambient temperature, the detector is always cooled in traditional on-line spectroscopic systems. However, measurement errors, such as wavelength drift, are still generated from the optical components when temperature changes. In addition, PCs are always used for system control and spectra acquisition, which significantly increase system instability. In order to solve these problems, this paper proposes an on-line thermostatic control spectroscopic system based on an STM32 single-chip microcomputer. Firstly, STM32 single-chip microcomputer is used to control the near-infrared spectroscopy for spectra data acquisition, configuration setting, preprocessing of the spectral data, and calculation of the physical and chemical parameters of the sample. Secondly, a constant temperature control system has been developed based onthe STM32 single-chip microcomputer, in which the proportional-integral-differential (PID) control algorithm is used. The closed-loop thermostatic control has been realized for the whole spectrometer, including the optical and the circuit part. At last, an industrial communication interface including Modbus protocol communication and 4~20 mA current signal communication has also been developed based on the STM32 single-chip microcomputer. The system test results show that the whole system can be operated stably without PC for a long time. The measure errors originating from the changing of ambient temperature also reduce obviously. During a test of 48-hour system operation, the temperature of the spectrometer is controlled stably at around (5±0.25) ℃. A much smaller relative standard deviation of absorption spectra is obtained when the thermostatic control is applied. The system integrates spectra acquisition, pretreatment, calculation of physical and chemical parameters, industrial communication and thermostatic control, which can satisfy the requirements of industrial on-line detection.
黄 超，赵宇红，张洪明，吕 波，尹相辉，沈永才，符 佳，李建康. 基于STM32单片机的在线恒温光谱分析系统研制与测试[J]. 光谱学与光谱分析, 2023, 43(09): 2734-2739.
HUANG Chao, ZHAO Yu-hong, ZHANG Hong-ming, LÜ Bo, YIN Xiang-hui, SHEN Yong-cai, FU Jia, LI Jian-kang. Development and Test of On-Line Spectroscopic System Based on Thermostatic Control Using STM32 Single-Chip Microcomputer. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2023, 43(09): 2734-2739.
