11.5 PRACTICE PROBLEMS

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(Note: Problem solutions are available at http://sites.google.com/site/automatedmanufacturingsystems/)

1. Convert the following flow chart to ladder logic.

2. Draw a flow chart for cutting the grass, then develop ladder logic for three of the actions/decisions.

3. Design a garage door controller using a flowchart. The behavior of the garage door controller is as follows,

- there is a single button in the garage, and a single button remote control.

- when the button is pushed the door will move up or down.

- if the button is pushed once while moving, the door will stop, a second push will start motion again in the opposite direction.

- there are top/bottom limit switches to stop the motion of the door.

- there is a light beam across the bottom of the door. If the beam is cut while the door is closing the door will stop and reverse.

- there is a garage light that will be on for 5 minutes after the door opens or closes.