MPU

Proximity switches open or close an electrical circuit when they make contact with or come within a certain distance of an object. Proximity switches are most commonly used in manufacturing equipment, robotics, and security systems. There are four basic types of proximity switches: infrared, acoustic, capacitive, and inductive.

Magnetic pickups (MPUs) are speed sensors that detect the speed of a prime mover, typically an engine or turbine. The MPU is installed next to a drive shaft gear made of a material that reacts to a magnetic field. As each gear tooth passes the MPU, the gear interrupts the MPU's magnetic field, and an alternating voltage is developed. The frequency of this voltage is translated by the speed control into a signal that accurately depicts the speed of the prime mover.