多通道超声波气体流量计的研制

Design of Multipath Ultrasonic Gas Flowmeter

文中针对大管径管道气体流量测量的高精度要求,采用可编程片上系统作为核心电路架构设计了一种多通道超声波气体流量计,将嵌入式处理器、数字逻辑控制、数字信号处理及人机交互控制等功能模块集中嵌入到单一的可编程逻辑器件(FPGA)芯片中,利用相关时差法提高超声波通道实时流速测量分辨率,并通过多通道流量模型修正和温度、压力补偿获得较高的流量测量精度和稳定性。所设计仪表功耗低、可移植性好,可用触摸屏设置参数及显示测量状态和结果,并具有故障报警提示和网络远程监控功能。

Aimed at the accurate measurement of the gas flowrate passing through a pipe with large diameter,one multipath ultrasonic gas flowmeter was introduced.The flowmeter was designed based on SOPC,in which all functional modules including MCU,DSP,numerical logic control and HMI control circuits were embedded in a single FPGA chip.A correlation peak-shift method was used to improve the transit-time difference and velocity resolution.A good accuracy and repeatability was obtained via an appropriate correction model to multi-path velocity profile and a suitable compensation for the gas pressure and temperature.System parameters can be set and measurement results were displayed on a TFT touch screen.A self-diagnosis and alarming function was provided and the meter can also be monitored and controlled by using a remote computer.