The Research Of Electromagnetic Flow-meter Signal Processing Method Based On Low Frequency AC Excitation

Electromagnetic flow meter is a new rate-flow measuring instrument based on the law of Faraday’s electromagnetic induction. As a primary measuring instrument, it rapidly develops with the development of electronic technology development. With its excellent performance, it is widely used in the industrial and agricultural production.The history of electromagnetic flow meter’s development and application is the history of its anti-jamming technology, in particular for the measurement of micro-flow signals. As the traffic signal is very small and the noise is large. So it is easily lost in the noise and results in measurement error. In dealing with the micro-flow signals, there are many signal processing methods which have been put forward. The various circuits have their advantages, but there are also some drawbacks. For the electromagnetic flow meter, excitation and signal processing technology are two important indicators on measuring its performance, which relate to its accuracy and stability. We propose the low-frequency AC excitation based on the electromagnetic flow meter signal processing method, which theoretically eliminates the orthogonal interference and the equal influence. And it also reduces the effect of other noise on the flow signal.This paper analyzes the main sources of interference and the exciting methods of electromagnetic flow meter, selects the method and the frequency of excitation, and focuses on the signal processing method under the low-frequency AC excitation. In the process of the electromagnetic flow meter signal processing method, with the elimination of the orthogonal interference and the equal influence, we minutely make a theoretical proof and simulate with the MATLAB, and finally derive the function expression of velocity signal combined with the practical application. For the proposed signal processing method, we design the hardware circuit and well elaborate the components of it. Then, based on the hardware platform of the design, we achieve the proposed signal processing algorithms and calibrate the relevant parameters in the velocity function combined with engineering practice, and finally determine the function of the flow velocity signal. From the experimental results, we can see that the method proposed in this paper is better than the signal processing method used in the peak sampling and holding in the elimination of the orthogonal interference and the equal influence with higher accuracy, and achieves a relatively good result in improving the measurement accuracy of electromagnetic flow meter.