Patent ID: 7689372

Claim:
Process for operating a measurement device of the vibration type, comprising: exciting at least one vibration-capable part of a measurement device to vibration using an adjustable excitation frequency ω of at least one exciter arrangement; determining from vibration parameters, a measurement quantity of a measurement medium within the at least one vibration-capable part of the measurement device, wherein a time-dependent force f(t)=F sin(ωt)+g(t) with at least one sinusoidal component having a force amplitude F, the adjustable excitation frequency ω, and with a possible extraneous time varying force factor g(t), acts on the at least one vibration-capable part of the measurement device and is driven using the exciter arrangement, and wherein a response signal of the at least one vibration-capable part is measured and a phase shift Ψ between the response signal and a signal component of the force f which oscillates with a frequency ω is determined; and using the phase shift Ψ as an input for a frequency controller so that the excitation frequency ω is automatically adjusted as a function of Ψ.