| 摘要 |
PROBLEM TO BE SOLVED: To correct zero-point errors, without exactly correcting the span and making the flow of objective fluid zero. SOLUTION: The electromagnetic flowmeter comprises the pairs of excitation coils 3 for impressing magnetic field on the fluid; a pair of electrodes 2a, 2b for extracting the firstδA/δt component (δ: partial differentiation symbol) and the first correction objective electromotive force and the secondδA/δt component of the second frequency and the second correction objective electromotive force; the span correcting part 51 for span correcting the first correction object electromotive force for correction, on the basis of the firstδA/δt component and for span correcting the second correction object electromotive force, on the basis of the secondδA/δt component; the zero-point correction part 52 for extracting the v×B component, by eliminating the thirdδA/δt component from either of two correction object electromotive force by extracting the thirdδA/δt component, on the basis of the corrected first correction object electromotive force and the second correction object electromotive force; and the flow rate output part 6 for computing the flow rate of the fluid from the v×B component. COPYRIGHT: (C)2006,JPO&NCIPI
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