A Reader’s Guide to Industrial Encoders


Several modern engineering applications have seen the use of use of encoders in their construction. In general terms, Encoders are the devices that converts data from one format to another. But, in the mechanical world the encoder is a type of sensor that develops digital signals from a power-driven motion. This is a type of device that analyses the position, velocity and direction of any electro-mechanical machine. And the data provided by the encoder is helpful in determining whether the system is working properly or not. There are different types of encoders available in the market.

  • Linear Encoders
  • Rotary Encoders
  • Position Encoders
  • Optical Encoders

Let us have a brief look at all of these.

  • Linear Encoders: This is a transducer with a reading scale that depicts the position of the moving object. This is measured by a cable that is connects the transducer and moving object. As the object keeps on moving the sensor keeps on detecting the position of the object. The sensor then converts this position into some analog and digital signal. Linear Encoders are of two types- absolute or incremental.
  • Rotary Encoders: This type of encoders determines the angular position of the rotating shaft and then generates an electrical signal as per the rotational movement of the device. There are different types of rotary encoders that are categorised as Incremental Rotary Encoders and Absolute Rotary Encoders.
  • Position Encoders: These are the types of encoders that records the linear position of some load or the rotary position of shaft through the rotary or linear encoders. As the name suggests, there are three different types to track the position: Indirect measurement with rotary, indirect measurement with linear and direct measurement.
  • Optical encoders: In this, the data is represented by light pulse. These pulses of lights are then used to determine the position, velocity or the direction of the moving object. A linear optical encoder gives the exact position of the object while a rotary optical encoder records the movement of the rotating shaft.

Since we learnt that encoders are broadly of two types: Absolute and Incremental, let’s have a look at both of them.

  • Absolute Encoders: It tracks an absolute numerical value for angular position on every revolution. There will be accurate determination of the position even after an event of power failure.
  • Incremental Encoder: These types of encoders generates a signal when the shaft undertakes a revolution for certain amount. For every reading, the counting begins from zero with no regard to its position.

So, in a nutshell encoders are used to create a signal that could be either incremental or absolute.

Do you know how an Encoder works?

The beam of light passes through a transparent disk that is surrounded by patterned lines. The light ray is detected by some photodiode or photosensor. This photodiode responds to the light beam by producing a sinusoidal wave form which gets transformed to some pulse train that is measured by the controller. For every 360 degree revolution of shaft, the incremental encoder defines a cycle. Every cycle that gets detected is closely monitored by a motion controller and convert them to counts to measure position or velocity.

The Various Applications of Encoder

Applications which require a feedback for operating perfectly in an environment requires encoders whether there is requirement for velocity, direction or position.

  • Automobiles: Encoders are in vast use in automotive industries to check and control the speed issues in the automobile.
  • Printers or other technical instruments: Encoders are utilized in these to detect the speed of printing or related functionalities.
  • Medical Equipment: Medical Scanners, digital microscope or some other automated device where the encoders are in use.
  • Scientific instruments: Testing instruments, Assembly machines and other gadgets that popularly use encoders for detecting the speed or position.
  • Military or warfare equipment: Encoders are used in antennas and other installation to detect the intrusion of any illegal interference.

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