基于热导原理的氢浓度测试系统设计

摘要

设计并实现了一种基于热导原理的氢浓度测试系统.设计热导原理气体传感器的信号调理电路,完成对微弱气体浓度信号的放大、滤波,提高信噪比,设计温度补偿电路,克服传感器温漂问题.调理后的输出信号经A/D转换器,由主处理器FPGA控制,完成模数转换.氢浓度信号以RS422标准协议送出,可远距离传输,通过RS422转USB通信模块送入计算机完成数据解析与显示.对测试系统开展标气考核实验,实验结果表明:该测试系统测量精度较高,测量范围较宽.%A kind of test system based on the principle of thermal conductivity of hydrogen concentration was designed and realized. Signal processing circuit of principle of thermal conductivity of gas sensor to amplify and filter the weak gas concentra-tion signal and improve the SNR was designed. Temperature compensation circuit was designed to overcome sensor temperature drift problem. After conditioning the output signal conversed by ADC,controlled by the main processor FPGA,analog to digital conversion was completed. Hydrogen concentration signal transmitted by the RS422 standard protocol can be long distance trans-mitted,and was sent into the computer to complete the data analysis and display through the RS422 to USB communication mod-ule. Test system was carried out standard gas assessment experiment.The experimental results show that the testing system has high accuracy and wide measuring range.