What is the function of using rotary encoders on elevators

First of all, the rotary encoder is used to monitor the elevator speed to achieve closed-loop control of the elevator; the elevator control system detects the speed through the rotary encoder, and obtains the linear motion data of the car through calculation.

Secondly, some elevators also realize the upward overspeed protection function through a rotary encoder, speed measurement and a brake device. Hope my answer can help you!