Patent ID: 7788046

Claim:
A Method for operating a magneto-inductive flow meter, comprising steps of: allowing a medium to be measured to flow through a measuring tube of a flow meter; producing a magnetic field, passing at least sectionally through the medium in the measuring tube with intensity varying as a function of time, in such a manner that a measurement voltage is induced, in the medium; tapping, by means of an electrode pair formed by first and second measuring electrodes, the measurement voltage induced in the medium, for producing an analog measurement signal corresponding with the measurement voltage, wherein the measurement signal has a wanted portion corresponding with an instantaneous flow velocity of the medium as well as a noise portion influenced at least in part by extant disturbances in the flowing medium; and ascertaining a flow-type of the medium located in the measuring tube, as determined by at least one of: an instantaneous flow profile and an instantaneous composition of the flowing medium, wherein the step of ascertaining the flow-type includes the steps of: producing a digital signal representing the at least one measurement signal; ascertaining, with application of the digital signal, a noise spectrum of the measurement signal, a band-limited noise spectrum corresponding, at least predominantly, with the noise portion; and ascertaining, with application at least of a part of the noise spectrum, at least one state value signaling at least qualitatively, as near-in-time as possible, a flow-type present in the measuring tube, wherein, the step of ascertaining the at least one state value comprises a step of ascertaining a spectral power density at least of the noise portion of the measurement signal.