How to select an encoder

May 7, 2019

Selecting the right encoder for your application can be a stressful task. With a variety of outputs, reading types and encoder body options to choose from, how can one get the best sensor for his application?

Some RLS encoders

Some of RLS encoders: AksIM-2, OnAxis, LM10

What is an encoder?

An encoder is a device that converts data from one format to another. In position sensing, an encoder can detect mechanical movements and convert them into an analog or digitally coded output signal. More precisely, it measures the position, while speed, acceleration and direction can be derived from the position in either linear or rotary motion.

There are different types of encoders according to their operating principle, purpose and complexity.

Most commonly, encoders are divided by the:

The linear encoder moves along the scale or ring and rotary encoder rotates around its axis. Learn more...

    • Incremental
    • Absolute

The difference between incremental and absolute encoders is similar to the difference between a stopwatch and a clock. Learn more...

    • Magnetic
    • Optical
    • Inductive
    • Laser

The position of the encoder can be measured using various physical principles. The information can be transmitted from the actuator to the readhead via light beam, electric current, electromagnetic field, induction, etc.

With a singleturn encoder, the output codes are repeated with each revolution of the encoder shaft. With multiturn absolute encoders, the output is unique for each shaft position at each revolution up to a certain number of revolutions (e.g. 4096).

    • High
    • Medium
    • Low

The resolution is the smallest movement detected by the encoder. It is measured differently depending on the type of encoder. Learn more...

There are many types of encoders, intended for various purposes, applications and end users.

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