INCREMENTAL OPTICAL ENCODER
DIFFERENCE BETWEEN ABSOLUTE ENCODER & INCREMENTAL OPTICAL ENCODER
2.absolute encoder have an unique position whereas in incremental encoder position is determined by counting the pulses from the zero reference.
3. absolute encoder are more complex then the incremental encoder.
4.incremental encoder outputs the pulse corresponding to the rotation angle by code only when in rotation condition. absolute encoder signal of position corresponding to the rotation angle by code.the absolute position from the starting point is measured by the output code data.
CONSTRUCTION AND WORKING OF THE INCREMENTAL OPTICAL ENCODER
As the disk starts to rotates the light is propagates through the transparent code and received by the photo detectors . these photo detectors generates the electric signal accordingly. in this case pulse is not a square type but it may be in the form of sine and cosine. it is require to place a comparator to change it in the form of square wave.
Here you can see their are two channels A & B. you can also see their output signals.signal of channel B is lagged by A at an angle of 90 degrees. this notation is useful to check or the direction of the rotation of the shaft.