4.6 ASSIGNMENT PROBLEMS

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1. What type of sensor should be used if it is to detect small cosmetic case mirrors as they pass along a belt. Explain your choice.

2. Summarize the trade-offs between capacitive, inductive and optical sensors in a table.

3. Clearly and concisely explain the difference between wiring PNP and NPN sensors.

4. a) Show the wiring for the following sensor, and circle the output that you are using, NPN or PNP. Redraw the sensor using the correct symbol for the sourcing or sinking sensor chosen.

5. A PLC has three NPN and two PNP sensors as inputs, and outputs to control a 24Vdc solenoid and a small 115Vac motor. Develop the required wiring for the inputs and outputs.