Encoder with wheel 

Power on the incremental encoder and measure the output voltage of A/B/Z. If there is none, the power supply is damaged or the main chip is damaged. If there is a phase, slowly rotate the shaft of the encoder. A/B should be in turn voltage From high level to low voltage, there is a 1/2 probability, and Z is a high level once in a circle. The high level voltage is generally 2V or higher than the input voltage. For example, a certain phase does not show a high level. Or the output level is very low, the phase is damaged

Split Encoder Absolute Encoder Incremental Encoder Pull Wire Encoder