Measuring Angular Displacement with an RVDT

Angular displacement is movement about an axis, such as the angular motion of the shaft of a motor. An angular displacement sensor is a device whose output signal represents the rotation of the shaft; it cannot measure the physical displacement of the whole shaft. One type of sensor that measures angular displacement is a rotary variable differential transformer (RVDT).

RVDTs are the rotational version of LVDTs and generally operate over a range of ±30°–70°. They are available in servo-mount and can rotate through 360° without encountering a stop.

RVDTs require special electronics designed for the sensor. RVDTs typically have a delay of 10 ms caused by required filtering in the signal conditioner. They are extremely rugged and operate over wide temperature ranges. In environments characterized by extremes in temperature and shock, an RVDT is the clear choice for rotational applications when you need more than 70° of measurement range.