How a Magnetostrictive Position Sensor Works
Send the stroke, output and mounting space — we recommend the magnetostrictive sensor type for your machine.
How does a magnetostrictive position sensor measure position without contact? This one-minute animation shows the current pulse on the waveguide wire, the Wiedemann-effect twist at the position magnet, the torsional wave travelling back at about 2,800 m/s, and position = wave speed × time.
Chapters
Key points
- A thin waveguide wire runs inside the stainless steel rod; a ring magnet moves with the piston, float or carriage.
- A current pulse on the wire meets the magnet field and twists the wire (Wiedemann effect).
- The twist returns to the head as a torsional wave at about 2,800 m/s while a timer measures the travel time.
- Position = wave speed × time: absolute position, no contact and no wear.
- SEGMENsensor magnetostrictive sensors cover strokes from 25 to 8000 mm.
Transcript
How does a magnetostrictive sensor measure position without contact?
Inside the stainless steel rod runs a thin waveguide wire. A ring magnet moves with the piston, the float, or the carriage.
First, the electronics send a short current pulse along the wire. The pulse creates a circular magnetic field.
Where that field meets the field of the magnet, the wire twists. This is the Wiedemann effect.
The twist travels back to the head as a torsional wave, at about two thousand eight hundred metres per second, while a timer measures the travel time.
Position equals wave speed times time. The result is absolute position, with no contact and no wear.
SEGMENsensor magnetostrictive sensors cover strokes from twenty-five to eight thousand millimetres. Learn more at segmensensor.com.