Processing Magazine

Magnetostrictive Sensor Provides Long Stroke Position Measurement

January 18, 2011

The long stroke linear position sensors provide highly accurate absolute position measurement of displacements up to 1.2 meters, according to the manufacturer. Available in ranges of 300- to 1,200-mm, these contact-less linear position transducers are ideal for hydraulic cylinder and actuator feedback applications where the sensor can either be mounted externally or embedded into the cylinder or actuator body. Utilizing magnetostrictive technology, the sensors operate by transmitting a current pulse through its tube that is reflected by a moveable permanent magnet. The sensor measures the time of flight to determine the position of the magnet on the tube. The time-based position measurement is translated into an output signal. Powered by 24VDC, the sensors have less than +/-0.25-percent linearity and +/-0.01-percent repeatability over the full scale with outputs that include analog voltage, current and SSI. As the magnetostrictive transducers provide absolute output, no data is lost should power be interrupted.