基于最小二乘法的脉冲流量计仪表系数的非线性修正

The non-linear correction of pulse flowmeter instrument coefficient based on the least square method

脉冲流量计输出的频率信号能够在较宽范围内保持良好的重复性,但其仪表系数只能在较窄的范围内保持恒定,从而制约了其测量精度。该设计提出以最小二乘法实现对脉冲流量计仪表系数的非线性修正,该方法基于Lab Windows/CVI来完成算法实现和流量修正软件的开发设计。最小二乘法的求解采用基于正交多项式集的构造途径,以相关系数对其拟合结果进行效果评价。频率测量采用嵌入式设备研华PCI-1710数据采集卡采集脉冲信号,并使用脉冲计数方式,解决了测量误差在总流量中的累积问题。软件为第三方软件提供了DDE通信的设备接口,实现了数据传输的标准化。该设计通过嵌入式控制手段模拟运行系统实现对流量的模拟测量,用测量所得数据生成的模型与标准模型相比较,结果表明该方法不仅提高了流量计的计量精度,而且展宽了其量程范围。

Pulse flowmeter output frequency signal can keep good repeatability in a wider scope,but the instrument coefficient can maintain a constant within a narrow range,thereby restricting its measuring accuracy. This design is on the least squares method to implement the algorithm,which is about non-linear modifying of pulse flowmeter instrument coefficient,also implement the algorithm and that the software development and design based on Lab Windows / CVI. It brings forward the way of pulse countinguses embedded system Advantech PCI- 1710 data acquisition card in flow measurement,to solve the problem that measurement error cumulates in the total flow. This software provides a DDE communications equipment interfaces for third- party software,and achieves the standardization of data transmission. The design through embedded system simulation systems,accomplishes the function of simulation to flow measurement. After compare the model generated by the measured data with the standard model,it turns out that not only the measuring accuracy of flowmeter has been improved,but also the measuring range has been broadened.