Method and apparatus for measuring mass flow

In a Coriolis mass flow meter, a sensor structure which produces a linear output signals proportional to the motion of the flow meter conduit to determine the relative mass flow of a fluid passing through the conduit. The sensor structure utilizing photo-optic type signal processing and interfaces the signal with a processor such that the signal is continuously calibrated to eliminate minor errors. The photoelectric structure also substantially isolates the electronic processing hardware and circuitry from mechanical as well as electric or magnetic interferences from the flow meter environment. The electronic interface comprising circuitry for determining the instantaneous amplitude difference between the signals from the sensors of the flow meter at a plurality of discrete and adjacent intervals, circuitry for determining the product of the absolute value of the instantaneous amplitude difference and the width of the interval for each interval, circuitry for determining the sum of the product for each interval over a cycle of oscillation, and circuitry for generating from the sum a signal representative of the mass flow.