Page 350 - Programmable Logic Controllers, Fifth Edition - Mobile version

CHAPTER 14 REVIEW QUESTIONS

1. Compare continuous and batch processes. 17. What information is contained in the process
2. Compare centralized and distributive control variable and control variable elements of a PID
systems. instruction?
3. State the basic function of each of the following as 18. State the function of each of the following elements
part of a process control system: of a PLC motion control system:
a. Sensors a. Programmable controller
b. Human-machine interface b. Motion module
c. Signal conditioning c. Servo drive
d. Actuators d. Servo motor
e. Controller 19. What does each axis of a robot arm function as?
4. State the purpose of each of the following types of 20. List four types of communication tasks provided by
screens associated with HMIs: local area networks.
a. Trend values 21. Name three common types of transmission media.
b. Operational summary
c. Alarm summary 22. What are the three general levels of functionality of
industrial networks?
5. What is the main characteristic of a closed-loop
control system? 23. Define the term node as it applies to a network.
6. State the function of each of the following parts of 24. Explain the physical layout of devices on a network
a closed-loop control system: for each of the following network topologies:
a. Set-point a. Star
b. Process variable b. Bus
c. Error amplifier 25. Compare device and process bus networks.
d. Controller 26. Define the term protocol as it applies to a network.
e. Output actuator 27. What is the function of a network gateway?
7. Explain how on/off control works. 28. Define the term access method as it applies to a
8. How does the proportional controller eliminate the network.
cycling associated with on/off control? 29. Summarize the token passing network access method.
9. Explain how a motor-driven control valve action 30. Summarize the collision detection network access
can provide analog control. method.
10. How does time proportioning provide analog 31. Summarize the polling network access method.
control?
11. What process error or deviation is produced by a 32. Compare parallel and serial data transmission.
proportional controller? 33. Compare half-duplex and full-duplex data
12. What term of a PID control is designed to eliminate transmission.
offset? 34. Explain how networking schemes minimize the
13. What does the derivative action of a controller amount of wiring required.
respond to? 35. What type of access control is used with DH+?
14. List the three gain adjustments used in tuning the 36. Compare the transmitting distances of RS-232
response of a PID control loop. and RS-422/485 serial types.
15. Compare manual, autotune, and intelligent tuning 37. What is DeviceNet used for?
of a PID controller. 38. List three pieces of information obtained from
16. How many input and output values are normally DeviceNet devices by the network scanner.
referenced in a PLC PID instruction? 39. What is ControlNet used for?

Process Control, Network Systems, and SCADA Chapter 14 331

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