What function does a limit switch serve in an elevator system?

A limit switch plays a critical role in an elevator system by detecting the position of the elevator car and ensuring that it stops at the designated landing. Limit switches are integral for safety, as their primary function is to confirm the car has arrived at the correct floor. When the elevator reaches its designated landing, the limit switch is actuated, signaling the control system to halt the car's movement, preventing any overshooting or potential accidents.

This mechanism is vital for the smooth operation of elevators, as it ensures that passengers are safely aligned with the doorway of the elevator when it stops, thereby minimizing the risk of accidents or injuries. The other options, while relevant to various aspects of elevator operation, do not directly relate to the specific function of a limit switch. For instance, controlling speed, activating alarms, or monitoring weight involves different components and systems within the elevator's design.