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Rotary encoder

Rotary encoder for industrial applications are used for Measurement of position, angle or distance used. The movement of machine parts is translated into a rotational movement which can be measured. Thus, the actual physical quantity can be determined with a conversion factor. The measurement signal that is evaluated and processed are pulses or an analogue signal. If pulses are used, the speed can also be measured if they are combined with a time value.

Encoder type

Measurement type


Rotary encoder as pulse generator

Per revolution, a number of Impulses which are issued by controllers, Preselection counters, or Process controllers is captured and processed. The pulses are generated by reading a graticule optically or magnetically. Each pulse corresponds to a value. With the help of calculations, the actual size of the distance, position, etc. can be determined. The higher the number of pulses per revolution, the higher the accuracy. A sensor that outputs 1000 pulses per revolution thus has a higher accuracy than a sensor that outputs 100 pulses per revolution.

The selection of the right variant can also depend on the components of the periphery. For example, if the length of a workpiece is to be measured and a measuring wheel with a circumference of 250 mm is used, it may make sense to choose a sensor with 250 pulses per revolution. In this case, the sensor's output of one pulse corresponds to the distance of one millimetre. Another example is the detection of an angle. If one chooses a variant that emits 360 pulses per revolution, one pulse corresponds to one degree.

Rotary encoder as analogue signal transmitter

Another possibility of measurement is the output of a Analogue signal. Here, the sensor outputs a precisely defined voltage depending on the position, for example 5 V at 360°. These rotary encoders are Absolute encoder and offer the advantage that the measured value is available immediately after switching on the machine, for example. These sensors are therefore ideal for detecting the position of machine parts.

Rotary encoder types

Depending on the area of application and mounting requirements, encoders are available in various housing sizes and options for connection to the periphery. For the connection there are variants with Solid shaft, Hollow shaft or Semi-hollow shaft. Furthermore, care should be taken to ensure a voltage-free connection in order to guarantee smooth operation. For this purpose Rotary encoder couplings can be installed as a link between the encoder and the machine, which ensure a stress-free connection due to their flexibility.

Encoder application areas

Rotary encoders are mainly used in industrial applications to measure the Position, Angle or Speed of machine components. The data supplied by the sensor can be used to control and run automated processes. Typical areas of application are, for example, milling machines, lifts, packaging machines or garage doors.