Coriolis mass flowmeter providing high accuracy, stable excitation with a short delay while employing digital signal processing

Abstract

First and second ΔΣ modulators convert output signals of two sensors into pulse density signals. First and second LPFs convert the pulse density signals into multi-bit signals. A signal computing module calculates a mass flow rate based on the multi-bit signals. A resonance circuit generates an excitation signal based on the output signals of the sensors. A drive output module amplifies the excitation signal. An exciter excites the measurement tube using an amplified excitation signal. A multiplier amplifies one of the pulse density signals to generate a multi-bit signal. An amplification factor controller controls an amplification factor of the multiplier based on the multi-bit signal. A third ΔΣ modulator converts an amplified signal into a pulse density signal. A DAC generates the excitation signal based on the pulse density signal.