Abstract: The invention relates to a method for operating an inductive flowmeter according to the preamble of patent claim 1. According to the invention, in order to minimise interfering signals, a receiving signal spectrum of all of the interfering signals is detected as a receiving signal, and the vector product between the receiving signal spectrum and a reference voltage is formed. An inverted Fourier transformation is then carried out and the thus obtained resulting signal is used to determine the flow rate.

Abstract: A method and device for obtaining an interference free measurement from a flowmeter. The flowmeter includes a measuring tube through which a flowable medium flows through a magnetic field generated by a magnetic arrangement and at least two measuring electrodes for detecting the measurement voltage induced by the flowable medium. The medium gives rise to interference voltages. The electrodes are connected to an interference-voltage eliminating unit by which common-mode interference is first eliminated by differentiation and unequal interference voltages are subsequently eliminated.

Abstract: The invention relates to a method and a device for determining the density and speed of a free-flowing medium according to the preamble of patent claims 1 and 4. In order to obtain a larger variety of evaluation possibilities, the flow speed and/or the density p are derived from the cited sensory variables, according to the field equation F=G×B+p×E.

Abstract: A method and device for detecting physical-chemical states on measuring electrodes (4a, 4b) of a flowmeter, through the measuring tube (1) of which a flowable medium (2) flows which, in doing so, passes through a magnetic field generated by a magnetic arrangement (3), wherein, for detecting the measurement voltage induced by the flowable medium (2), at least two measuring electrodes (4a, 4b), which are connected to a following interference-voltage eliminating unit (6) by which common-mode interference is first eliminated by differentiation, are arranged at the measuring tube (1), wherein unequal interference voltages are subsequently eliminated by the interference-voltage eliminating unit (6) in that, in operation, the current voltage value U+(n) and U?(n) of each individual measuring electrode (4a; 4b) is compared with the associated preceding voltage value U+(n?1) and U?(n?1), a measurement being released for further signal processing only when as a result of the comparison, an equal, essentially proportion