Abstract: The invention relates to a magnetic-inductive measuring device (1) for flowing substances (substance being measured), with at least one subsystem respectively for carrying substance (hydraulic system, measuring tube) (2), for recording measuring signals, comprising a signal pickup (electrode arrangement (20, 22) for signal tapping), for generating a magnetic field, comprising at least two exciting coils (30) and a ferromagnetic core (32) (magnetic system), and for bounding the device on the ambient side (housing), and is characterized in that at least one of the subsystems is entirely or partly formed by layers of fibre composite material and/or is embedded in layers of fibre composite material.

Abstract: A circuit for detecting faults in a magmeter system in which an electrically conductive fluid flows which is maintained at a reference potential. The circuit includes at least two electrodes in contact with the fluid. The electrode signals are conducted to the corresponding inputs of a measuring circuit. An alarm circuit is connected ahead of the measuring circuit. A difference in the magnitude of the values (+U.sub.S and -U.sub.S) of the electrode signals and/or non-symmetries in the noise content of the electrode signals and/or a disturbance in the high frequency signal (U.sub.G) in a loop which contains the electrodes and a high frequency producing generator causes an alarm to be activated.