The control needed for the first and third floors is relatively simple because the elevator must always go down to reach the first floor and always go up to reach the third floor. This control can be accomplished by starting the motor up or down and permitting the appropriate limit switch to stop the motor when it reaches the designated floor. Interlocking is also a necessity to prevent the UP and DOWN motor starters from being energized at the same time. When the third-floor push button is pressed, the UP starter energizes and the elevator starts up. When it reaches the top, limit switch LS3 opens and stops the motor. At the same time, the normally open LS3 contact closes and turns on the green pilot light to indicate the elevator is on the third floor. When the first-floor push button is pressed, the DOWN starter is energized and the elevator starts moving in the downward direction. When the elevator reaches the first floor, the normally closed limit switch LS1 opens and stops the motors and the normally open LS1 limit switch closes and turns on the red pilot light. Design a control circuit that will fulfil the give requirements.
[
[