Magnetostrictive Level Transmitters: How They Work

Magnetostrictive level sensor
Magnetostrictive level sensor
(courtesy of MTS)
Magnetostrictive level sensors are similar to float type sensors in that they both use a permanent magnet sealed inside a float which travels up and down a rod. The difference is the use of a magnetostrictive element sealed inside the rod.

Magnetostrictive level sensors provide continuous level measurement with high accuracy, and are very effective for use in a variety of liquids. In many applications they are used in conjunction with magnetic level gages (Mag Gage) to provide visual indication along with an analog or digital output.

Magnetostrictive level transmitters charge a magnetostrictive element with electric current. When the element's electromagnetic field intersects the float's magnetic field, a mechanical pulse is created. The pulse then travels back down the element at the speed of sound. Similar to ultrasonic or radar level transmitters, the distance is measured by time of flight, which corresponds to the distance from the sensor detecting the return pulse.

Here is a short video visually demonstrating the magnetostrictive principle:

Here is a more in-depth video demonstrating how a magnetostrictive level transmitter works:

Video created by Tony Kuphaldt and Bellingham Technical College and used here under Creative Commons Attribution 3.0 Unported license.

For more information on magnetostrictive level control, contact:

Power Specialties
9118 E. 72nd Terrace
Raytown, MO 64133
Toll Free: (800) 432-6550
Phone: (816) 353-6550
Fax: (816) 353-1740