涡街流量计数字信号处理系统的改进与实验

Improvements and Experiments of Digital Signal Processing System for Vortex Flowmeters

本文针对涡街流量计数字信号处理系统存在的不能测量小流量和易受电磁干扰的问题 ,对其软硬件方面进行了改进。重新设计和研制了电荷放大器 ,提高了灵敏度 ,增强了适配能力。采取了合理的接地和屏蔽措施 ,提高了系统的抗干扰能力。采用去均值和频谱校正的方法 ,改善了系统的测量精度。编制键盘监控软件 ,采用状态变量法设计键值分析程序 ,实现人机对话功能。进行了液体流量和气体流量的标定实验 ,结果表明 ,改进后的数字信号处理系统比常规的流量计信号处理系统的测量精度高、流程比宽和适配能力强。

In order to resolve the problems of the digital signal processing system for vortex flowmeters, such as the small flow cannot be measured and the system is subjected to the electromagnetic interferences. this paper improves the software and the hardware of the digital signal processing system. A charge amplifier is again designed and developed to raise its sensitivity and enhance its adaptability. Reasonable grounding and screening are adopted to ensure the anti-disturbance of the system. Through removing mean and frequency spectrum correction, the measurement precision of system is improved. The software of keyboard monitor is developed, the analysis program of key value is designed using the state variable method, and the functions of man-machine talk are implemented. The calibrating experiments of gas flow and liquid flow are made, and the results show the performance indexes of the digital processing system are better than that of the conventional instruments, such as the measurement precision, the ratio of measuring range and the adaptability.