What is the difference between an absolute encoder and an incremental encoder?

Incremental encoders generally output signals are two quadrature pulse signals and one reference signal. The reason why it is called incremental is because its position signal is obtained by accumulating pulse counting, and it relies on the internal memory of the counting device to remember the position, and The same as the reference signal output every turn to clear the accumulated error. The disadvantage is that after the power is off, you need to find the initial position again. For example, the positioning of the printer scanner is based on the principle of incremental encoder. Every time you turn on it, you can hear it. There is a bang, it is looking for the reference zero point, and then it works. The absolute encoder is divided into single-turn absolute and multi-turn absolute. Single-turn absolute, measuring each engraved line of the photoelectric encoder during rotation to obtain a unique code , 360 degrees does not repeat, when the rotation exceeds 360 degrees, the code returns to the original point; and multiple turns can keep n turns without repeating, depending on the specific choice, the principle is similar to the principle of the clock gear mechanism, of course, there is also an electronic ring recording. Most Japanese absolute encoder products.

From the above description, it can be concluded that the difference is that the absolute can be directly applied, and the incremental must be calculated to be obtained.