wHow do elevators move to the same exact spot every single time the button is pressed?

Question

I work in a hotel and ride elevators upwards of 50 times a day. Never once has the bottom of the elevator been even a fraction of an inch above or below the floor where the elevator begins. Assuming there is a minimal amount of slippage in the cabling, how do the elevators move the exact same distance every single time? Is there some sort of cable/feet math going on where each floor is x amount of motor turns?

In: Engineering

Answer 1

The sensors are built into the elevator shaft (either above the doors or the rails). You may have noticed that the cabin slows down when coming to the floor and then crawls for a couple of seconds before coming to the full stop. That’s done so it can stop the moment it hits the sensor and not over/undershoot the door.