Encoder Glossary！

Absolute Encoder – provides the shaft position in a bit configuration and is able to maintain or provide absolute position even after instances of power loss/failure. 

Accuracy – difference in distance between the theoretical and the actual position. 

Cycles Per Revolution (CPR) – Cycles per revolution are the number of output pulses per complete revolution of the encoder disk. 

Encoder –is a sensor of mechanical motion that generates digital signals in response to motion. 

Incremental Encoder – device that provides a train of pulses due in response to mechanical motion. The output of this encoder is in form of a square-wave. 

Index – a separate output channel which provides a single pulse per shaft revolution. It can be used to establish a reference or marker for a starting position.

Interpolation – is the method of increasing the resolution of an encoder. This method allows for the encoder to produce a higher resolution output without increasing the overall size of the disk and encoder. 

Line Driver – is a sourcing output. This means that when in ‘ON’ state the line driver will supply Vcc and in the ‘OFF’ state the driver will float. A sinking input is required for line driver applications. 

Open Collector – is a sinking output. In the ‘OFF’ state, an open collector will be grounded and in the ‘ON’ state, the open collector will float. A sourcing input is required for open collector applications. 

Pulses Per Revolution (PPR) – the total number of pulses produced per full revolution of the encoder shaft. 

Push-pull - is a combination between a line driver and an open collector. In the ‘OFF’ state it will be grounded and in the on ‘ON’ state it will supply Vcc. 

Quadrature Encoder – two output channels which are out of phase by 90 electrical degrees. From the phase difference, the direction of rotation can also be determined. 

Resolution – number of line increments on a disk. Resolution for incremental encoders is often referred to as cycles per resolution and for absolute encoders it is in terms of bits. 

Square Wave – a repetitive waveform corresponding to high and low signals. 

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