Magnetorestrictive distance measurement systems made by our partner Balluff have gained a firm foothold in the sector of plant engineering and automation. Typical fields of application of magnetorestrictive micropulse transducers are tasks where high reliability and precision are necessary. Integrable or compact designs and measuring lengths between 25 mm and 7600 mm make these distance measurement systems universally applicable.
Contactless, precise and absolute measurements are convincing reasons for the broad industrial application of linear, magneto restrictive transducers. Expensive service calls and inconvenient downtime are avoided through the contactless and wear-free method. The operational principle allows to place the devices in hermetically sealed housings, since the current position is transferred through the housing wall to the inset sensor via magnetic fields without direct contact. In principle, it is possible to measure multiple positions with one measuring system simultaneously. Magnetorestrictive distance measurement systems attain IP-ratings IP67 and IP69K without laborious, complex and error-prone sealing concepts. Their high resistance against shock and vibration loads further extends their industrial field of application into the area of heavy machines and plant engineering. The measured values and position data which are available as absolute values immediately after the startup of the system are mandatory for many applications and increase the machine availability significantly by omitting the reference runs.
|machine tools and injection molding machines |
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high protection class / codes
The measuring element, a waveguide, is made of a special nickel-iron-alloy with 0.7 mm outside diameter and 0.5 mm inside diameter. A copper conductor is threaded through this pipe. The measurement is initiated by a short current pulse. This current creates a circular magnetic field which is concentrated on the waveguide because of its soft magnetic properties. A permanent magnet is placed as a position sensor at the measurement point. Its field lines run perpendicular to the magnetic field of the pulse and are also concentrated on the waveguide.
Because of magnetostriction, a micro scale elastic deformation which creates a mechanical wave spreading in both directions occurs in the waveguide section where both magnetic fields overlap. The propagation velocity of this wave is 2830 m/s and is mostly insensitive against environmental influences (e. g. temperature, vibration, staining). The wave propagating towards the end of the waveguide fades there, while the wave propagating towards the transducer creates an electric signal by reversing the magnetostrictive effect. The wave travel time from the point of origin to the transducer is directly proportional to the distance between permanent magnet and transducer. This distance can be measured via time measurement with high accuracy.