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7.4 ASSIGNMENT PROBLEMS

1. Use the Karnaugh map below to create a simplified Boolean equation. Then use the equation to create ladder logic.

2. Use a Karnaugh map to develop simplified ladder logic for the following truth table where A, B, C and D are inputs, and X and Y are outputs.

3. You are planning the basic layout for a control system with the criteria provided below. You need to plan the wiring for the input and output cards, and then write the ladder logic for the controller. You decide to use a Boolean logic design technique to design the ladder logic. AND, your design will be laid out on the design sheets found later in this book.

There are two inputs from PNP photoelectric sensors

part and

busy.

There is a NO

cycle button, and NC

stop button.

There are two outputs to indicator lights, the

running light and the

stopped light.

There is an output to a conveyor, that will drive a high current 120Vac motor.

The conveyor is to run when the

part sensor is on and while the

cycle button is pushed, but the

busy sensor is off. If the

stop button is pushed the conveyor will stop.

While the conveyor is running the

running light will be on, otherwise the

stopped light will be on.

4. Convert the following truth table to simplified ladder logic using a Karnaugh map AND Boolean equations. The inputs are A, B, C and D and the output is X.