PLC Chapter 4

5. The following symbol in an RLD represents a A. temperature switch B. flow switch C. float switch D. pressure switch

A. temperature switch

15. You can use a PLC output port A. to run a large motor B. to start a large motor C. to start a large conveyor D. to start a large generator

A. to run a large motor

19. Which of the following statements is false? A. A solenoid opens or closes a valve when a PLC commands it to do so. B. A solenoid only opens a valve when a PLC commands it to do so. C. A motor starts when a PLC commands it to do so. D. None of the above.

B. A solenoid only opens a valve when a PLC commands it to do so.

18. Which one of the following switches cannot be referred to as a limit switch? A. Float switch B. Standard SPST switch C. Wobble stick D. Roller switch

B. Standard SPST switch

14. In a relay device, you can find A. multiple coils and NO or NC contactors B. one coil and multiple NO and NC contactors C. one coil and one NO contactor D. one coil and one NC contactor

B. one coil and multiple NO and NC contactors

12. There are A. only active triangulation systems B. only passive triangulation systems C. active and passive triangulation systems D. None of the above.

C. active and passive triangulation systems

11. In a triangulation sensing system,_ A. distance is measured B. direction of the location of an object is detected C. both distance (i.., range) and direction of an object is detected D. None of the above.

C. both distance (i.., range) and direction of an object is detected

2. The following RLD symbol is classified as a A. single-pole, single-throw, single-break B. single-pole, double-throw, single-break C. double-pole, double-throw, double-break D. double-pole, single-throw, double-break

C. double-pole, double-throw, double-break

3. The following RLD symbol is classified as a A. double-pole, double-throw, single-break B. double-pole, double-throw, double-break C. double-pole, single-throw, double-break D. double-pole, single-throw, single-break

C. double-pole, single-throw, double-break

4. A double-pole, double-throw (DPDT) switch has A. 3 terminals B. 4 terminals C. 5 terminals D. 6 terminals

D. 6 terminals

17. Which of the following statements is false? A. A Hall effect sensor can be used instead of a reed switch. B. A proximity sensor can be used instead of a limit switch. C. A solid state temperature sensor can be used instead of a thermocouple. D. A float switch instead of a pressure switch.

D. A float switch instead of a pressure switch.

6. Which of the following statements is false? A. A liquid level switch is sometimes called a float switch. B. A proximity switch can be used instead of a limit switch. C. A proximity switch can be used instead of a level switch. D. A flow switch can replace a pressure switch.

D. A flow switch can replace a pressure switch.

10. Piezoelectric sensors can generate a(n) signal when a part is detected. A. AC voltage B. AC current C. DC voltage D. All of the above.

D. All of the above.

13. A solenoid is used to control the A. flow of air B. flow of liquid C. flow of gas D. All of the above.

D. All of the above.

16. To protect an electric motor, one can use a A. temperature overload relay B. magnetic overload relay C. temperature and magnetic overload relay D. All of the above.

D. All of the above.

20. Optical sensors can use A. visible light B. infrared light C. laser light D. All of the above.

D. All of the above.

7. There are electronic sensors that can be used to mimic A. human sight and hearing B. human touch and taste C. human smell and hearing D. All of the above.

D. All of the above.

8. An electronic proximity sensor can have a(n) A. LED and phototransistor B. radar transmitter and receiver C. sonar transmitter and receiver D. All of the above.

D. All of the above.

9. Which one of the following sensors can replace a limit switch? A. Inductive sensor B. Capacitive sensor C. Proximity sensor D. All of the above.

D. All of the above.

1. A single-pole, single-throw (SPST) switch connected to a discrete input can send A. an ON or OFF signal to the PLC B. a logic 1 of logic 0 to the PLC C. only an ON signal to the PLC D. Both A and B.

D. Both A and B.