在线补偿天然气流量积算仪

设计了基于ARM9核心的天然气流量积算仪,接收流量变送器输出的模拟信号、脉冲信号或HART信号,设计了压力传感器和温度传感器接口电路;基于WinCE平台上开发了系统软件,输入天然气各种组分及其摩尔分数或百分比后,根据AGA8-92计算方法建立起压缩因子和温度、压力关系的三维数据表,为了保证实时性,利用线性插值方法快速求出测量工况下的压缩因子,将天然气体积流量折算为标准状态下的体积流量,实现在线补偿.可输出4～20 mA电流和脉冲.

Design of Natural Gas Flow Totalizer with Online Compensation

A natural gas flow totalizer based on ARM9 was designed, the outputs signal of flow transmitter such as analog signal, impulse signal or HART signal are available for the system, and the pressure measuring circuit and temperature measuring circuit are designed. The software was developed on WinCE platform, after the component and the fraction of natural gas are input, the relations between compressibility factors and pressure, temperature are established according to the AGA8-92 calculation method. To guarantee the online compensation, a linear interpolation is proposed to obtain the compressibility factors of any working condition, and then reduce the volume flow of natural gas at working condition into volume flow at standard condition. The output of the system is from 4 mA to 20 mA current or impulse signal.