【摘要】 本文介绍了低功耗混合型流量积算仪的功能要求和技术指标 ,比较了恒压法和恒流法两种传感器供电方法对测量精度的影响 ,设计了系统的组成和接口 ,分析了各个模块的功耗 ,确定了芯片的选型和系统的工作频率 ,并提出采用分时给三个传感器加恒流源激励的方法 ,结合 A/ D转换芯片的开关功能和 CPU的睡眠功能 ,可以实现系统的低功耗要求。最后 ,提出了保证系统测量精度的方法。实践表明 ,采用上述方法可以较好地实现系统的功能、低功耗要求和精度指标 ,温度、压力和差压的测量精度都优于0 .2 %。更多还原

【Abstract】 In this paper,the function requirements and technical specifications of low power mixed flow totaliz- er are introduced,effects of two exciting methods— voltage excitation and current excitation on measurement accuracy are compared,system composition and its interface are designed,power consumption of every module is analyzed,chip selection and operation frequency of system are determined,an exciting method for three sen- sors sharing one current source at different time is proposed. Aided with on- off function of A/D device and sleep function of CPU,the low power requirement is met. Atlast,measure for improving system measurement accuracy is proposed. Application shows that system functions,low power requirement and accuracy specifica- tions are implemented easily using measures mentioned above,measurement accuracies of temperature,pres- sure and differential pressure are less than0 .2 % .更多还原