Incremental vs. absolute encoders

A very common classification of encoders is based on the encoding principle. The difference between incremental and absolute encoders can be seen as the difference between a stopwatch and a clock. A stopwatch measures the relative time that elapses between its start and its stop, so you can read the time by adding the value of the elapsed time. A clock, on the other hand, shows the exact current time within a day.

Similar to a stopwatch, an incremental encoder indicates the relative position and direction of movement by adding incremental pulses to a known start position. An absolute encoder can be compared to a clock, because it reads the unique magnetisation pattern of a scale or ring and therefore knows the absolute position.

Incremental and absolute magnetic scale