Study Of The Key Technology Of Outflow Electromagnetic Flowmeter

Electromagnetic flowmeter is based on Faraday's law of induction of the flow velocity,because of its simple structure,no moving parts,sensitive response and other advantages,in the industrial field of measurement has been widely used.In actual measurement,the signal amplitude from sensor is small,and is mixed with interference noise,so the SNR is very low.Study on how to suppress and eliminate the interference,extend measurement lower limit,and improve metering accuracy and stability are the focuses of the study of electromagnetic flowmeter.This article introduces the domestic and international current situation,and development trend of electromagnetic flowmeter are reviewed.The article elaborates the measuring principle of electromagnetic flowmeter,and designs an outflow electromagnetic flowmeter based on DSP controller of the low frequency rectangular wave excitation mode.The article gives the overall block diagram of system,hardware circuit diagram and software modules of system diagram.In the hardware circuit system,the article completes the electromagnetic flowmeter excitation system,signal conditioning circuit,A/D conversion circuit,and DSP peripheral interface circuit design;in view of the narrowband filter for signal conditioning circuit in system,the article applies a current in each cycle the invariable average excitation current source of electromagnetic flowmeter excitation system for power supply.In view of the DSP chip powerful operation ability and speed of operation,the article adds digital filter module in the electromagnetic flow meter software system.With the aid of the Embedded Target for TI C2000 DSP development tool,through the establishment of MATLAB/Simulink simulation model,the article completes the FIR digital filter design.In the end this article uses the flow speed signals which are outputted by the current electromagnetic flowmeter sensor and processed after through the signal regulate circuit as the experimental data to realize digital filter algorithm processing on DSP and verify effectiveness of arithmetic in signal denoising.The outflow electromagnetic based on DSP has strong signal processing ability,and the research provides the theory basis for the future of electromagnetic flowmeter signal processing.The research has certain practical application value and the twice development value.