Abstract: Systems and methods are directed to method and device operating a flow meter. The flow meter including electrodes which can be used to feed a signal into fluid to be measured. A signal E1i in the form of a current or a voltage is applied to at least one first electrode. A response signal is measured at another electrode E2i which does not receive the signal or is not currently activated, to record a diagnosis the flow meter and the changes in the consistency of the flowing medium at any time during measurement operation. Impedances are determined and/or voltage(s) and/or current(s) are measured, wherein these values are set in comparison/ratio with previous values and the status of the device and/or of the measurement medium is deduced both qualitatively and quantitatively.

Abstract: The invention relates to a method and a device for operating a flow meter, in particular magnetically inductive flow meters but also capacitive meters, as well as those which comprise electrodes which can be used in order to feed a signal into the fluid to be measured, according to the preamble of patent claim 1. In order to record a diagnosis both of the meter per se, but also of the changes in the constitution or consistency of the flowing medium at any time during measurement operation, according to the invention a signal E1i in the form of a current or a voltage is applied to at least one electrode and, at another electrode E2i which does not receive the signal or is not currently activated, impedances are determined and/or voltage(s) and/or current(s) are measured, wherein these values are set in comparison/ratio with previous values and the status/a perturbation of the device and/or of the measurement medium is deduced first qualitatively and then quantitatively therefrom.