How magnetostrictive sensors work

Magnetostrictive sensors are characterized by high reliability and precision in position and speed measurement. They can be installed in hermetically sealed housings as they transmit the current position information via magnetic fields contactlessly through the housing wall to the internal magnetostrictive sensor element. Thanks to their high resistance to shock and vibration, they are suitable for heavy machinery and plant construction.
The sensor element – the waveguide – is a metallic tube made of magnetostrictive material into which a copper conductor is threaded.

Design principle of magnetostrictive sensors

During the measuring process, the excitation current pulse induces a circular magnetic field, which is bundled thanks to the soft magnetic properties of the waveguide. A permanent magnet (in the illustration called position magnet) which is mounted on the moving component to be measured, serves as a passive position sensor. At the measuring point, both magnetic fields overlap at right angles and deform the waveguide minimally by magnetostriction. The elastic deformation generates a mechanical wave that propagates to both sides at 2,850 metres per second. The induction coil at one end of the waveguide converts the mechanical wave into a current pulse so that the evaluation electronics can precisely determine the position on the basis of the wave propagation time. At the other end of the waveguide, a damping element prevents disturbing reflections of the mechanical wave. ▪

Author: Dr. Detlef Zienert, Press Relations Manager, Balluff GmbH

Find out more now!

SENSOR+TEST 2019 starts soon

The leading international trade fair for sensor, measuring, and testing technology – SENSOR+TEST – will be held from 25 - 27 June 2019 at the Nuremberg Exhibition Center.

The SENSOR+TEST is a must-go venue for developers and engineers from all industries as well as for technically oriented engineering and science students. Without today’s sensor and measuring technology, appliances, machines, systems, and industrial processes could not be designed according to the state of the art or further developed in view of future innovations. Moreover, without the latest testing technology, the ever-increasing standards of quality could not be met within the cost limits imposed by external factors. There is no comparable platform where innovative users can meet so many important suppliers of sensor, measuring, and testing technology from all over the globe. With the special topic "Sensor and Measuring Technology for Process Automation" the SENSOR+TEST 2019 picks up the ongoing trend of the digitization in this very interesting scope of application. Exhibitors involved in this field will present their solutions and concepts on the special forum, on their booths and in lectures. The trade fair with about 540 suppliers, two forums for company presentations, as well as the 20. GMA/ITG-Fachtagung "Sensoren und Messsysteme" offers efficient and comprehensive technical information. The AMA Association for Sensors and Measurement and AMA Service as organizers expect more than 8,000 visitors. ▪ ds

Find out more now!