APG MPX Slave Sensor user manual - Manual (Page 4)

MPX Series Magnetostrictive Level Sensors
Rev. B, 4/13
4
Automation Products Group, Inc.
APG...Providing tailored solutions for measurement applications
Tel: 1/888/525-7300 • Fax: 1/435/753-7490 • www.apgsensors.com • [email protected]
• How does it work?
The MP series level sensors are based on magnetostrictive technology.
Inside the stainless steel stem is a wire waveguide made of a metal that has
magnetostrictive properties. Magnetostrictive means that the atoms in
the metal realign in the presence of a magnetic field causing the metal to
temporarily deform or elongate very slightly. Inside the float(s) are permanent
magnets. When a quick pulse of current is sent through the wire waveguide,
the magnetic field generated by the current pulse interacts with the magnetic
field of the float(s) to realign the atoms in the waveguide. This results in a
rapid torsion that sends vibrations through the waveguide at near the speed
of sound. The sensor picks up the vibration pulse, and through precisely
measuring the time elapsed between the current pulse and the torsion
vibration, determines with precision the location of the float. The MP has the
capability to simultaneously monitor two floats on a single stem, giving it the
ability to measure an oil/water interface level in addition to the total tank level.