Three switches Sw1, Sw2, Sw3 are connected to inputs 000

National Institute of Design and Analysis PeshawarExercise # 1

PLC Training Module # 1

Introduction to PLCs Hardware & Software

Problem # 1

Consider a conveyer belt is moving bottles on it. Juice is being filled in bottles. At first stage a sensor S1 is available to check if the bottle is properly filled. At second stage a sensor S2 is available to check if the cover is properly pasted on the bottle. At third stage a sensor S3 is available to check if the correct label is pasted on the bottle. Draw a ladder diagram to turn ON the output LED, if all the input conditions are true.I/O Table

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Problem # 2Room Temperature Controller

Consider a room in which an air conditioner, a heater and two temperature sensors S1 and S2 are installed. Sensor S1 will turn ON only when room temperature goes below 23C. Sensor S2 will turn ON only when room temperature goes above 25C. Design a Ladder Diagram for the following conditions.

If room temperature is below 23C then turn OFF AC and turn ON heater.

If room temperature is above 25C then turn ON AC and turn OFF heater.

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Problem # 3Consider a tank in which liquid is to be filled. A sensor S1 is available at the bottom of the tank to indicate if the tank is empty. A Valve V1 is available to fill the liquid in the tank. Draw a ladder diagram to fill the tank. When tank will be empty, sensor S1 will turn ON. Then turn ON the valve for 20 seconds and turn it OFF.

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Problem # 4Consider a circuit with three Switches Sw1, Sw2, Sw3, three LEDs L1, L2, L3 and one buzzer B1. Draw a ladder diagram to measure the priority of Switches.

If Sw1 turns ON first, then turn On L1, turn OFF L2 & L3 and beep the buzzer for 1 second.

If Sw2 turns ON first, then turn On L2, turn OFF L1 & L3 and beep the buzzer for 1 second.

If Sw3 turns ON first, then turn On L3, turn OFF L1 & L2 and beep the buzzer for 1 second.

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Problem # 5Automatic Door ControllerThis problem demonstrates about the entrance / exit door automation. A door is installed with two sensors S1 and S2, which detects human presence at both sites of gates. a motor is installed to open and close the door. Two limits Switches are installed at extreme ends of door to stop the motor.

Draw a ladder diagram to perform the following automation.

1. Gate will be opened if any of sensors detects human presence.

2. Gate will remain open until any one sensor is ON.

3. Gate will be closed after a delay of 3 seconds when both the sensors will be OFF.

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Problem # 6Consider the situation in problem #1. Turn ON the filling process and Turn it OFF after filling 15 bottles.

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Problem # 7Packing ControlThis problem demonstrates about the conveyer belt B1 being rotated by a motor M1. It has a sensor S1 at a specific position.

When the system will power ON, motor M1 will turn ON to move the conveyer belt B1, which contains apples.

When an apple passes in front of sensor S1, it will generate a pulse and apple fall in a box.

Count 10 apples and stop the motor M1.

Note: Solve the problem without using counter.

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