Encoders

When it comes to precision motion control, an encoder is an essential component that translates mechanical motion into electrical signals. Used in many applications such as automation equipment, industrial process control, or robotics, encoders provide data on position, speed, distance and direction.

There are three main encoder technologies on the market to choose from: magnetic, optical and capacitive.

A rotary encoder responds to rotational motion whereas linear encoders respond to motion along a linear path. A rotary encoder is often referred to as a shaft encoder. It is an electro-mechanical device that converts the angular position or motion of a shaft to analogue or digital output signals. There are two main types of rotary encoder: absolute and incremental. An absolute encoder generates unique bit configurations to track positions directly. An incremental encoder generates a train of pulses which can be used to determine position and speed.

Linear encoders monitor linear movement and provide position feedback in the form of electrical signals. Movement is determined from changes in position with time. Both optical and magnetic linear encoder types function using this type of method. In servo driven systems, linear encoders supply the precise position of the load, typically in addition to the speed and direction feedback provided by the motor’s rotary encoder. For stepper driven systems, which typically operate in open-loop mode with no position feedback, adding a linear encoder increases the accuracy and reliability of the positioning system without the cost and complexity of a servo motor.