阈值控制的电磁流量计偏置调节方法  

Threshold control based bias adjustment method for electromagnetic flowmeter

作　　者：梁利平[1] 徐科军[1,2] 张然[1] 张振[1] 

机构地区：[1]合肥工业大学电气与自动化工程学院,合肥230009 [2]工业自动化安徽省工程技术研究中心,合肥230009

出　　处：《电子测量与仪器学报》2013年第1期89-96,共8页Journal of Electronic Measurement and Instrumentation

基　　金：863计划重点(2008AA042207);重庆市科学技术委员会(CSTC 2008AB2059)资助项目

摘　　要：电磁流量传感器输出信号存在低频漂移的偏置干扰,若不处理就直接放大,会使运放饱和,导致电磁流量计无法正常工作。一种基于阈值控制的偏置调节方法。在系统初始化阶段,计算偏置调节系数K;在流量测量过程中,根据阈值判断信号是否需要调整偏置;若需要调整,则在下一个励磁周期的开始时刻更新DAC输出,一次性将信号偏置调整回零伏附近。该方法避免了频繁调节偏置,保留了信号的原始特性,便于后续处理。针对调整过程所产生的阶跃干扰,改进了数字信号处理算法,确保测量精度。仿真实验和实际水流量标定实验证明,该偏置调整方法是可行的和有效的。There is the low frequency drift bias interference in the electromagnetic flow sensor output signal. If the signal is amplified directly without processing, the amplifier will be in saturation, and the electromagnetic flowmeter cannot work normally. Therefore, a threshold control based bias adjustment method is proposed in this paper. In the initialization stage of the system, the adjustment coefficient K is calculated. During the flow measurement process, whether the signal needed to be adjusted is determined according to the threshold. If the bias adjustment is needed, the DAC output will be updated at the beginning of the next excitation cycle to adjust the signal bias to zero voltage at one time. This method avoids frequent bias adjustment, retains signal＇s original characteristics, and facilitates subsequent processing. The digital signal processing algorithms are improved by removing the step interference caused by the bias adjustment, and the measurement accuracy is ensured. The simulation and the water flow calibration experiments show that the bias adjustment method is feasible and effective.

关 键 词：电磁流量计 偏置调节 信号处理 梳状带通滤波 DSP 

分 类 号：TH814[机械工程—仪器科学与技术] TN9[机械工程—精密仪器及机械]