面向微弯型科氏质量流量计的高精度过零检测算法实现

Implementation of high-precision zero-crossing detection algorithm for micro-bend type Coriolis mass flowmeter

针对已有微弯型科氏质量流量计测量小流量时精度低、重复性差的问题,设计了高精度信号输入调理电路,并将两级滤波器与四点拉格朗日插值的过零检测算法相结合用于微弯型科氏质量流量计的信号处理。在以TMS320F28335为核心的科氏质量流量变送器上,实时实现整套算法,并将研制的变送器与微弯型科氏质量流量传感器相匹配,进行了零点稳定性测试和水流量标定实验。实验结果表明,整套算法可行有效,实现了微弯型科氏质量流量计对小流量的高精度测量。

To solve the problem of micro-bend type Coriolis mass flowmeter＇s low accuracy and poor repeatability in the measurement of small flow,a high-precision signal conditioning circuit is designed,and a method consisting of two-stage filter and digital zero-crossing detection using four-point Lagrange interpolation is applied to micro-bend Coriolis mass flowrneter.The whole algorithm is implemented in real time on a Coriolis mass flow transmitter developed with TMS320F28335 chip.The zero-point test of meter and the water flow calibration are performed by connecting the transmitter with the micro-bend type primary instrument.The experimental results show that the algorithm is feasible and effective,and the high-precision measurement of small flowrate using micro-bend Coriolis mass flowmeter is realized.