Model Study Of Electromagnetic Flowmeter Signal Between Electrode Based On The Sinusoidal Excitation

Electromagnetic flowmeter as an advanced flow measuring and testing instrument,and has been widely used in water treatment which liquid conductivity must bigger than 5us/cm, medicine and food, industrial production, etc. but electromagnetic flowmeter signal between electrode has some complicated composition, it's hard to purify that differential interference mix in eddy current magnetic field. Electromagnetic flowmeter of signal between electrode processing method adopted widely at home and abroad is to use software to process, through program control sampling time and get the mean of sampling signal, Software signal conditioning has some advantages,such as high performance affiliate marketing,agile and changeable and so on. but this method overdependence output signal accuracy, this bottleneck can't to satisfy the higher accuracy demand. With the deepening of practical application, the methods of electromagnetic flowmeter signal disposal improved also demanding. Therefore, In this paper,analysis the electromagnetic flowmeter signal modeling between electrodes, puts forward new signal processing method based on the hardware design, and the signal processing algorithm enhances the electromagnetic flowmeter measurement precision.Through the analysis of electromagnetic flowmeter principle of work base on Faraday's electromagnetic induction law and get the interference, alternating current produce "eddy current" effect and electromagnetic flowmeter work magnetic field overlaped, and differential interference exist in the "eddy current" produced superposition magnetic field, according to the mode of action about signal between electrode, established the mathematical model of electromagnetic flowmeter signal between electrode, use a two-step fitting algorithm on parameters, according to the experimental data, establish the signal model between electrode, a quantitative description the relationship of electromagnetic flowmeter electromotive force signal between electrode and exciting voltage with the flow signal. Using quadrature demodulation method, pick up the traffic signal from the electrodes signal which mixed with a differential interference, provides an effective treatment methods about differential interference elimination under the sinusoidal excting. According to the electromagnetic flowmeter signal between electrode model design electromagnetic flowmeter hardware circuit, recuperate the output signal by two parts: the DC signal and AC signal, the DC signal with pipe flow rate signal is a linear relationship, namely useful flow signal. Through this method will Separating useful flow signal from interference signals, analysis the experimental results, the results show that the effection of signal modeling method of electromagnetic flowmeter measurement accuracy and practical value.Project work for improving of electromagnetic flowmeter measurement accuracy has an important meaning, and proposed the theory lay the necessary foundation for the study of later electromagnetic flowmeter electrode between signal modeling, this model has a certain universality, provided theoretical basis of reference to the other excitation type of electromagnetic flowmeter, therefore, the studies of this paper has certain theoretical meaning and practical value.