青藏高原冻土温度64通道监测系统设计

Design of 64 Channel Monitoring System for Frozen Soil Temperature in Qinghai-Tibet Plateau

为了服务青藏高原铁路建设需要,本文在分析青藏高原冻土水热物理特性基础上,研究了冻土测试专用热敏电阻的非线性特性,通过实验逐点测试传感器温度值并进行分段拟合,得到热敏电阻的阻温关系曲线。结合青藏高原恶劣自然环境,设计了一种适应于青藏高原不同深度冻土温度监测系统。引入四线制方法,巧妙地设计了64通道温度监测电路,实现了不同深度冻土温度监测功能。根据测试精度要求,提出一种温度校正方法,解决了热敏电阻测量不稳定,信号畸变等问题。经过系统性能分析与实验室测试,结果表明系统能够满足不同深度冻土温度监测精度要求,功耗较低,具有良好的工作性能。

In order to serve the needs of railway construction in Qinghai-Tibet Plateau,this paper studies the nonlinear characteristics of the dedicated thermistor for frozen soil testing based on the analysis of the hydrothermal physical properties of the frozen soil in the Qinghai-Tibet Plateau.The temperature values of sensor are tested point by point through experiments,segmented fitting of the relationship of temperature & register curve.In combination the above step,the relationship of temperature & resistance curve for thermistor is obtained.Combined with the harsh natural environment of the Qinghai-Tibet Plateau,a temperature monitoring system for different depths of the Qinghai-Tibet Plateau was designed.A 64-channel temperature monitoring circuit was skillfully designed with the four-wire method to realize different depths of frozen soil temperature monitoring.According to the requirements of test accuracy,a temperature correction method is proposed to solve the problems of unstable thermistor measurement which resulting in signal distortion.After analysis of system performance and laboratory testing,the results show that the system can meet the requirements of different deep frozen soil temperature monitoring accuracy,low power consumption and good working performance.