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Non-contact Position Measurement

Product News Thursday, July 14, 2011: Variohm Euro Sensor

New membrane/magnetic potentiometer technology offers high protection, compact size. The MagnetoPot is new non-contacting linear potentiometer based upon a fully sealed membrane strip and a simple magnet that together provide position feedback from 8 mm to 1200 mm in a low profile and robust design with exceptionally long life capability. Manufactured by USA based membrane sensor experts Spectra Symbol, and available exclusively in the UK from Variohm EuroSensor, the MagnetoPot is ideal for hydraulic and pneumatic position sensing and other medium precision position feedback applications such as liquid level monitoring.

A rotary version is also available for compact, low profile angle sensing. The MagnetoPot is similar in concept to a traditional membrane type potentiometer but rather than use a contacting wiper to connect the collector to the resistive element, relies upon the interaction of a non-contacting external magnet and an encapsulated magnetic or ferromagnetic strip to determine the electrical output and hence relative position. The thin IP 65 membrane has a typical membrane thickness of less than 3.5 mm - allowing the position sensor to be discretely installed with either the magnet or the membrane strip attached to the moving component.

The standard linear MagnetoPot is available in eleven travel range versions from 12.5 mm to 1000 mm with a choice of 3-pin connection options including Crimplex solder tabs, male pins and a variety of connectors. The electrical specification includes a 10 kO resistance output over each linear position range (5 kO to 500 kO on request) with a linearity of +/- 5%. The positioning resolution is dependent upon the exterior magnet strength and its proximity to the MagnetoPot's magnetic strip. The rotary version is currently available with a 66 mm diameter and an active centre track diameter of 46 mm.

The IP65 rating for the active area for both types of MagnetoPot allows for intense water spray and the non-contact technology effectively yields an extremely long and maintenance free working life.