A Coriolis
mass flow measuring device includes a vibratory measuring
transducer having at least one measuring tube, which has medium flowing through it during operation. In operation, the measuring tube is caused by an
exciter arrangement to undergo mechanical oscillations, especially bending oscillations. Additionally, the Coriolis
mass flow measuring device includes a sensor arrangement for producing oscillation measurement signals (s1, S2) representing the inlet-end and outlet-end oscillations of the measuring tube. Measuring device
electronics controlling the
exciter arrangement produces an
exciter current (iexc) and an intermediate value (X′m) derived from the oscillation measurement signals (s1, s2). This intermediate value represents an uncorrected
mass flow. Derived from the exciter current and / or from a component of the exciter current (iexc), an intermediate value (X2) is produced, which corresponds to a damping of the oscillations of the measuring tube. This damping is especially a function of an
apparent viscosity, and / or a
viscosity-density product, of the medium guided in the measuring tube. Furthermore, a correction value (XK) is produced for the intermediate value (X′m) utilizing the intermediate value (X2) and a
viscosity measurement value (Xη) determined initially or during operation. The
viscosity measurement value (Xη) corresponds to a viscosity of the medium guided in the measuring tube and / or to a predetermined reference viscosity. On the basis of the intermediate value (X′m) and the correction value (XK), the measuring device
electronics then produces an exact mass flow
rate measurement value (Xm).