| Vortex flow-meter is a developing device for measuring flow rate, and it has more and more application in industrial field, and the accuracy of measuring result is directly determined by vortex signal. Though FFT algorithm is easy to be realized in engineering field, it has a shortage of bigger error. After considering several kinds of advanced signal processing algorithm, ZOOM-FFT is selected to process vortex signal. After the signal is treated by digital low-pass filter, a narrow band containing vortex signal is obtained. Meanwhile, the narrow band is extracted with integer multiple to decrease sample rate before calculated by FFT with the same points as the original signal processing by means of FFT only. Using this method, the frequency spectrum is got refinement.During the process of ZOOM-FFT, the extracting multiple of narrow band is firmly related to the final result. So, fuzzy algorithm is put forth to realize on-line automatic adjustment of extracting multiple. In the fuzzy logistical system, the approximate value of vortex frequency obtained by FFT calculation is taken as the system input, and the interval of input and output varieties and their membership functions is built by simulation, and finally the extracting multiple is obtained by fuzzy rules determined by actual extracting principle.A field-bus system for intelligent vortex flow-meter is discussed also. The design content includes the selection of transmission media, topological structure and data transmission mode. The concept of redundant configuration is brought forth in network interface module, and varied redundant configurations are to meet varied requirements. Meanwhile, the synchronizing communication realized by main clock is discussed, and the solution is brought forth to prevent system from breakdown due to main clock's fault.
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