The KOBOLD NMT level meter is a highly accurate float-controlled sensor for continuous sensing of levels. The instrument is comprised of two parts: 1) A magnetostrictive sensor in the measuring tube 2) An integral, four-wire transmitter with the connection box KOBOLD NMT uses the principle of echo time measurement. A magnetostrictive wire is tensioned in the measuring tube. Current pulses are transmitted through the wire and generate an annular magnetic field around the wire. The wire is then magnetized axially by magnets fitted internally to the float. When the magnetic fields align, a torsional impulse is generated which ropagates with ultrasonic speed in both directions. The distance from the float magnet to the predefined zero-point is measured by an echo time measurement. The integrated electronics then convert the time signal to a standard 4-20 mA analog signal. The magnetostrictive technique yields a measurement with very high accuracy and resolution.
