The measuring device (waveguide) is made of a special iron-nickel alloy and has an external diameter of 0.7 mm and an internal diameter of 0.5 mm. A copper conductor runs along the entire length of this tube. The measurement process is initiated by a short current pulse. This current generates a magnetic field, which propagates by rotating along the waveguide. At the measured point of the path, a permanent magnet is used as a marking element, the field lines of which are directed at right angles to the electromagnetic field.
In the area of the waveguide where both magnetic intersect, the magnetostrictive effect leads to elastic deformation of the waveguide (deformation at the micro level), which generates a mechanical wave propagating in both directions. The propagation velocity of this wave in the waveguide is 2830 m / s and is practically insensitive to external factors (for example, temperature, shock loads, pollution).
The part of the wave that reaches the far end of the waveguide is suppressed, while the signal entering the signal transducer becomes electric due to the inverse magnetostriction effect. The wave propagation time from the point of origin to the transducer is in direct proportion to the distance between the permanent magnet and the signal transducer. Thus, the measurement of time allows you to determine the distance with exceptional accuracy.