In using a rotary encoder process, it will tangle rotary encoder selection problem, to solve this problem, up Electronic commonly used two kinds of rotary encoder selection process Notes summary description below:
　　1 incremental rotary encoder Selection Considerations
　　(1) Mechanical dimensions, including shaft, mounting holes; cable and outlet; installation space volume; environment protection level meets the requirements.
　　(2) resolution, which work when the encoder output pulses per turn, whether to meet the design requirements for the use of precision.
　　(3) electrical interface, the encoder output common push-pull output (F-type HTL format), output voltage (E), open collector (C, C is the common type NPN output tube, C2 PNP type tube output), long-term driver output. Its output should and its control system interface circuit to match.
　　2, absolute rotary encoders Selection Considerations
　　(1) Mechanical part
　　① measuring length or angle measurement, measuring length how mechanically converted (some described above, such as do not know can call to discuss). Measured angle is 360 degrees (lap), or may be over 360 degrees (multi-turn). Production process is a rotation cycle work, or back and forth direction of the cycle work.
　　② shaft installation form, connected by a flexible shaft coupling type, or sleeve-type connector.
　　③ use of the environment: dust, moisture, vibration, shock?
　　(2) the electrical part
　　① output receiving moiety
　　② signal form
　　③ resolution requirements
  ④ control requirements
　　In short, before using a combination of factors to consider which aspects of the rotary encoder to choose a suitable, if in doubt and we welcome the discussion.