From single-turn absolute encoder to the multi-turn absolute encoder

   Single turn absolute rotary encoders to measure the rotation of the optical encoder of the Road engraved lines to obtain a unique code, when rotated more than 360 degrees, the encoding back to square one, this is not consistent with the principle of an absolute encoder only, so coding
It can only be used to rotate 360 degrees within the range of measurement, known as single-turn absolute encoder.
    If you want to measure more than 360 degrees of rotation, it is necessary to use multi-turn absolute encoder.
    Encoder manufacturers use mechanical watches gear principle, when the center of rotation of the code wheel, through another set of code wheel gear (or set of gears, multiple sets of code disk), single-turn encoder, based on the additional number of turns coding, to expand the encoder measuring range, this is called absolute encoder multi-turn absolute encoder, it is also determined by the mechanical position encoders, each location code unique non-repetition, without memory.
Another advantage of the multi-turn encoder is due to the large measuring range, the actual use is often more affluent, so that the installation of unnecessary hard to find zero, as a starting point to an intermediate position on it, and greatly simplifies the installation difficult.