热式气体流量计信号采集电路的设计与研究  

Design and Research of Signal Acquisition Circuit of Thermal Gas Flow-Meter

作　　者：唐明[1] 赵志龙[1] 

机构地区：[1]西北工业大学机电学院,陕西西安710072

出　　处：《测试技术学报》2014年第2期154-157,共4页Journal of Test and Measurement Technology

基　　金：西北工业大学研究生创业种子基金资助(Z2014045)

摘　　要：首先介绍了气体流量测量的必要性及影响其测量精度的主要因素,并介绍了热式气体流量计测量气体流量的原理,推导出流体流速与电流之间的表达关系式.根据定温法测量原理,分析了惠斯通电桥电路的作用.然后设计了热式气体流量计信号采集电路,并分析了电路的工作原理及其温度补偿作用,介绍了其优点及创新之处.通过实验研究,得到流量与输出电压的实验数据;对数据进行拟合处理,得到流量与输出电压的表达关系式.实验结果表明:信号采集电路基本消除了因流体温度变化引起的测量误差,提高了系统的测量精度,基本达到工业生产的要求.The necessity and the main factors affecting the measurement accuracy ot the gas tlOW as well as the measurement principle of thermal mass flow sensor are introduced. The related expression of flow velocity and current is given. According to the constant temperature measurement principle, the role of the Wheatstone bridge is analyzed and a signal acquisition circuit is designed and analyzed which can compensate the influence of the changes of gas temperature. Advantages and innovations of the circuit are introduced. Experimental data of flow and output voltage is obtained by experiment. By fitting the data, the expression of the relationship between the flow and the output voltage is ob- tained. The result shows that the measurement error caused by fluid temperature changes is basically removed and the measurement accuracy is improved, which basically reaches the requirements of in- dustrial production.

关 键 词：热式气体流量计 信号采集电路 温度补偿 惠斯通电桥 数据拟合 

分 类 号：TH814[机械工程—仪器科学与技术]