Mass flowmeter methods, apparatus, and computer program products using correlation-measure-based status determination

Abstract

Motion signals representing motion of a conduit of a mass flowmeter are mode selective filtered to generate a plurality of mode selective filtered motion signals such that the plurality of mode selective filtered motion signals preferentially represent motion associated with a vibrational mode of the conduit. A plurality of time difference estimates is generated from the plurality of mode selective filtered motion signals. A correlation measure is generated from the plurality of time difference estimates. A status of the mass flowmeter system is determined from the generated correlation measure. In some embodiments, the correlation measure comprises an intercept parameter of a scaling function that relates the plurality of time difference estimates to a plurality of reference time differences representing motion of the conduit at a known mass flow. In other embodiments, the correlation measure comprises a correlation coefficient estimated from the plurality of time difference estimates. In still other embodiments, the correlation measure comprises an error of estimate. The mass flowmeter system status may be determined by determining a change in the correlation measure, and corrective action may then be taken if the determined change satisfies a predetermined criterion. The invention may be embodied as methods, apparatus and computer program products.