An encoder is an electromechanical device that
provides an electrical signal that is used for speed and position control.
Encoders turn mechanical motion into an electrical signal that is used by the
control system to monitor specific parameters of the application and make
adjustments if necessary to maintain the machine operating as desired. The
parameters monitored are determined by the type of application and can include
speed, distance, RPM, position among others. Applications that utilize encoders
or other sensors to control specific parameters are often referred to as
closed-loop feedback or closed-loop control systems.
Video Source By- Learning Engineering
There are two main different type of encoder:-
Rotary Encoder:-
A rotary encoder, also called a shaft encoder, is an
electro-mechanical device that converts the angular position or motion of a
shaft or axle to an analog or digital signal.
There are two main types: Absolute and Incremental.
The output of absolute encoders indicates the
current position of the shaft, making them angle transducers. The output of incremental encoders provides
information about the motion of the shaft, which is typically further processed
elsewhere into information such as speed, distance and position.
Rotary encoders are used in many applications that
require precise shaft unlimited rotation Including industrial
controls, robotics, special purpose for photographic lenses, computer input
device, and rotating radar platforms.
Linear Encoder:-
A linear encoder is a sensor, transducer or readhead
paired with a scale that encodes position. The sensor reads the scale in order
to convert the encoded position into an analog or digital signal, which can
then be decoded into position by a digital readout or motion controller.
The encoder can be either incremental or absolute.
Motion can be determined by change in position over
time. Linear encoder technologies include optical, magnetic, inductive, capacitive
and eddy current.