Visi-Trak Worldwide LLC, Charlottesville, VA, offers the #A40-HR 20P linear position and velocity sensor system that provides better than 0.001 in. resolution at over 200 in./s. The system combines a transducer paired with an encoded rod. As the rod moves, the sensor uses GMR signal acquisition technology to detect movement, sampling at 2 kHz. An anti-aliasing encoder interface overcomes the sampling limitations imposed by the Nyquist effect to allow sampling <0.001 in. at speeds greater than 200 in./s with no contact between the rod and transducer. Encoded rods are available in 10 and 20 thread/in. and 1 and 2 mm pitches. The auto-calibrating device can sense virtually any stroke length making it suited for use with hydraulic and pneumatic cylinders and linear actuator applications.
