The best way to distinguish between an incremental encoder and an absolute encoder is to consult the manufacturer's selection manual. This is because encoders involve many parameters, such as the protection level of the housing, the size of the encoder shaft, the flange type and connection type, the output circuit and output signal, the number of pulses, etc. Sometimes, they may not be compatible just because of a single letter difference.
However, to simply determine whether an incremental encoder is an absolute encoder, a rule of thumb is to look at the wiring diagram on the nameplate. Incremental encoders usually have 8 wires, and the wiring symbols are: u, gnd, a, a (reverse), b, b (reverse), z or o, z or o (reverse).
Absolute encoders typically have a large number of lines (represented by two-color patterned wires), and their wiring symbols are: u, gnd, 2^0, 2^1, 2^2, 2^3, 2^4, 2^5, 2^6, 2^7, 2^8...
The above are just general encoders. There are many other types of encoders. When purchasing, it is best to consult the manufacturer's selection manual.
