Density measuring device

Abstract

The density measuring device serves for measuring density, ρ, of a flowable medium and comprises a measuring device electronics (ME) as well as a measuring transducer (MT) electrically connected therewith. The measuring transducer includes a measuring tube (), an oscillation exciter () for exciting and maintaining oscillations and an oscillation sensor () for registering oscillations of the at least one measuring tube. The measuring device electronics is adapted by means of an oscillation measurement signal (s) as well as an exciter signal (e) to adjust a drive force effecting wanted oscillations (namely oscillations with a predetermined wanted frequency, f) of the measuring tube. The drive force is adjusted in such a manner that during a predetermined phase control interval a phase shift angle, φ, by which a velocity response, V, of the measuring tube Is phase shifted relative to a wanted force component, F, of the drive force, is less than −20° and greater than −80°, and/or the wanted frequency has a frequency value, which corresponds to greater than 1.00001 times, equally as well less than 1.001 times, a frequency value of an instantaneous resonant frequency of the measuring tube. Moreover, the measuring device electronics is adapted based on the oscillation measurement signal (s) present during the phase control interval to ascertain at least one frequency measured value, X, which represents the wanted frequency for the phase control interval, as well as also with application of the frequency measured value, X, to generate a density measured value, X, representing a density, ρ.