What's inside an encoder and how it works? | electronics automation

Encoders are widely used in machines tool and robots to provide positional information for the CNC.
But what's inside an encoder? Are you curious to see it?

Encoders are important devices used in machines, robots, vehicles, laboratory instrumentations and more, to gauge linear or angular positions. In this video a couple of encoders are opened to see what's inside, and learn how they work.

Encoders are devices that encode the position into a numerical signal. While magnetic, contact and more types of encoder do exist, in this video only optical encoders are discussed.
They can be linear or rotational giving the information of their position along a straight line, for linear encoders, or along a full revolution for rotational encoders. And they can be absolute or incremental.
The most common used encoder is the rotational incremental encoder, that usually comes with two or three channels. So their typical application is to provide an angular position, such as on an arm of a robot, or a converted linear to angular position in machines such as CNC machines when coupled with a lead screw that moves a carriage through the rotation of a motor and an attached encoder.
The internal electronic circuit is usually made of a photo detector that read from a disc (or a stripe in the case of linear encoders) where a number of marks or slots are printed or cut out, making the light to pass through. Follows a comparator that discriminates the light level and prevents uncertainties, making the reading stable, and a line driver circuit to output the signals.


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