为了实时实现适用于水流量和浆液流量测量的高频励磁控制和数字信号处理算法,同时,使变送器具有较为完备的人机接口和通信功能,采用梳状带通滤波算法处理水流量信号,并基于信号重构算法处理浆液流量信号.充分、合理地利用DSP的资源,设计硬件系统,实现仪表的各种功能.巧妙、灵活地安排励磁控制、信号处理、人机接口、数据通信之间的时序,研制DSP软件.通过配置20 ms的定时器中断,并在其中断服务程序中采用中断嵌套的方式,确保励磁控制和信号处理的实时性.将执行时间较长的液晶刷新显示子程序和按键操作子程序放置在主循环中,以便其他模块的正常执行.所研制的DSP软件系统适用于矩形励磁或三值励磁下的水流量和浆液流量的测量.对研制的高性能电磁流量变送器进行算法实时性测试和水流量标定试验,取得了较好的试验结果.%In order to implement the high frequency excitation control and the digital signal processing algorithm in real time for the flow measurement of water and slurry;and to make the transmitter have a more complete man-machine interface and communication functions,the comb bandpass filtering algorithm is adopted to process the signal of water flow,and based on the signal reconstruction algorithm,the signal of slurry flow is processed.The resources of the DSP are reasonably and fully utilized,and the hardware system is designed to realize various functions of the instrument.The time sequence among excitation control,signal processing,man-machine interface,and data communication is skillfully and flexibly arranged,and the software of DSP is developed.A 20 ms timer interrupt is configured,and interrupt nesting is applied in interrupt service program,so as to ensure the real time performance of both excitation control and signal processing.The liquid crystal refresh display subroutine and the key operation subroutine which requires longer execution time are put in the main loop,so other modules can be executed normally.The DSP software developed is suitable for measuring water and slurry flow under rectangular excitation or three-value excitation.The real time performance test of algorithm,and water flow calibration test are conducted for the developed high performance electromagnetic flow transmitter,and good experimental results are obtained.
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