Discrete-State Process Control

Work the problems below.  To receive any credit, you must show all work.  You may submit your work in a word processing document or in a pdf file.  Graphic files are not acceptable submissions.  Your file submission document should be entitled Week7AYourGID (replace YourGID with your specific GID).

  1. Produce a ladder diagram that will cause output Y  to go HIGH when switch A and B are closed OR when switch C is closed.  (Hint:  Start with the Boolean equation).
  2. Design the ladder diagram for a new Ford truck door/safety belt system.  When the truck door is open and the seat belt is not clicked in, the truck will not start.  If door is closed and seat belt is clicked in, the key will start the ignition.
  3. Create a ladder diagram to control a washing machine. This washing machine would have a fill cycle to one level, a 10 second wash cycle, a 10 second rinse cycle and then drain. Include a start button, low level switch, high level switch, an agitator motor, a fill valve and a drain valve.
  4. A control system is needed to control a small shopping center parking lot lighting system and the exterior lighting for the building. The design specifications require that the parking lot lighting and the exterior lighting turn on at dusk automatically. The parking lot lighting should automatically turn off at midnight but the building exterior lighting should remain on until dawn when it is turned off automatically. The system should repeat daily and should not require adjustment for the change in the seasons. Locate and specify an appropriate sensor if it is to operate at 120 vac as an input to a PLC. Create the ladder diagram to accomplish the specified control. Paste the sensor specifications into your document.