Absolute Encoders output the rotational angle using an absolute code. The rotational position can be detected by reading the code. This eliminates the need to return to the origin at startup.
There are 3 products of Absolute.
Low-cost Encoder with Diameter of 50 mm
E6CP-A
General-purpose Absolute Encoder with External Diameter of 50 mm
Slim Encoder with Diameter of 50 mm
E6C3-A
Rugged Rotary Encoder
Absolute 60-mm-dia. Rotary Encoder
E6F-A
Rugged Rotary Encoder