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A Brief Introduction Of Absolute And Incremental Encoders

Aug 28, 2017

                                           A brief introduction of Absolute and Incremental Encoders

An absolute encoder maintains position information when power is removed from the system .The position of the encoder is 

available immediately on applying power. The relationship between the encoder value and the physical position of the controlled 

machinery is set at assembly; the system does not need to return to a calibration point to maintain position accuracy. An 

"incremental" encoder accurately records changes in position, but does not power up with a fixed relation between encoder 

state and physical position. Devices controlled by incremental encoders may have to "go home" to a fixed reference point to 

initialize the position measurement. A multi-turn absolute rotary encoder includes additional code wheels and gears. A high-

resolution wheel measures the fractional rotation, and lower-resolution geared code wheels record the number of whole 

revolutions of the shaft. An word representing the absolute position of the encoder within one revolution. This type of encoder is 

often referred to as a parallel absolute encoder. An incremental encoder works differently by providing an A and a B pulse 

output that provide no usable count information in their own right. Rather, the counting is done in the external electronics. The 

point where the counting begins depends on the counter in the external electronics and not on the position of the encoder. To 

provide useful position information, the encoder position must be referenced to the device to which it is attached, generally 

using an index pulse. The distinguishing feature of the incremental encoder is that it reports an incremental change in position 

of the encoder to the counting electronics. Visit us for more info www.ttmotor.com  Nice Day !!