Data-Replacement Based Anti-Strong Low-Frequency Instantaneous Impact Vibration Signal Processing Method And Low-power Implementation For Vortex Flow Meter

Vortex flowmeter is widely used in petroleum, chemical and other industries with the advantages of no moving parts, long service life, large measurement range and suitable for measuring a variety of media. Since the vortex flowmeter belongs to fluid vibration flowmeter, it is often unable to work normally with the strong low-frequency instantaneous impact vibration interference in practical industrial sites. Aiming at this problem, the domestic and foreign researches focused on improving the structure of vortex flow sensor to enhance the ability of anti-instantaneous impact vibration, did not put forward an effective anti-instantaneous impact vibration signal processing method. When there is continuous or strong instantaneous impact vibration, vortex flowmeter still cannot measure the correct fluid flow.In this paper, the knocking vibration is performed to simulate the strong low-frequency instantaneous impact vibration. According to analyzing the features of vortex flow sensor output signal with the strong low-frequency instantaneous impact vibration interference, a data-replacement based anti-strong low-frequency instantaneous impact vibration signal processing algorithm is proposed. In addition, this paper puts forward a frequency spectrum analysis method based on real FFT and assembler, and also proposes a two average and accelerated method. These methods not only save the memory space and reduce the computation time, but also enhance the ability of anti-strong low-frequency instantaneous impact vibration of vortex flowmeter and improve the display speed of vortex flowmeter.Based on the anti-strong low-frequency instantaneous impact vibration signal processing method in this paper, MATLAB simulation program is developed. The output signal of vortex flow sensor is processed by the software form different direction, knocking force, knocking frequency and medium flow.Based on the anti-vibration digital signal processing hardware system which is developed by our research group with MSP430F5418 low-power MCU, the software with anti-strong low-frequency instantaneous impact vibration signal processing method is developed, and the gas flow rate measurement experiments are performed under the strong low-frequency instantaneous impact vibration interference. By the proving of experimentation, when the flow is none or small, the signal processing system can correctly display the vortex flow frequency with the knocking of horizontal and vertical direction,40 times/10 seconds knocking frequency and larger knocking force on the pipeline. When the detected knocking number is more than four times in a data processing time (one second), this signal processing system can predict and give self-diagnosis. When the flow is large, it has been unable to detect knocking vibration in the time domain signal. However, the vortex flow signal is strong enough to obtain the correct vortex flow frequency by the direct spectrum analyses.