1) When ON switch, input I0.0 will automatically start the parking lot, when Sensor1 is working, Motor1 will be activated. Open the barrier gate and after Sensor1 stops working for 5 seconds, it will command Motor1 to stop working to close the barrier gate.

2) When Sensor2 is running, it will command Motor2 to open the exit barrier gate and after Sensor2 stops working for 5 seconds, it will command Motor2 to stop working and close the barrier gate.

3) The timing of Sensor1 deactivation will result in Counter1 counting.

4) Stopping Sensor2 will cause Counter1 to count down.

5) When the number of cars in the parking lot reaches 40, the full car sign will be activated, prohibiting the entrance gate from being opened.

When turning on the input switch I0.1, the system stops all operations.

13) Design a Ladder Diagram program from the Timing Diagram as follows.

Sensor1 Sensor1