44. List five important procedures to follow when han- 45. Define each of the following terms as they apply to e. BASIC or ASCII module dling statie-sensitive PLC components f. Stepper-motor module the memory clement of a PLC a. writing 36. List one application for each of the following intel- ligent VO modules a. PID module e. bits d. location e. utilization b. Motion and position control module e. Communication module 37. Write a short explanation for each of the following discrete VO module specifications: 46,With reference to the VO image tables: a. What information is stored in PLC input and a. Nominal input voltage output tables? h. What is the imput status of a closed switch b. Input threshold voltages c. Nominal current per input stored as? c. What is the imput status of an open switch d. Ambient temperature rating e. Input ON/OFF delay f. Output voltage stored as? d. What is the status of an output that is ON g. Output current stored as? e. What is the status of an output that is OFF h. Inrush current i. Short circuit protection stored as? J. Leakage current 47. Why do PLCs execute routines? k. Electrical isolation L. Points per module m. Backplane current draw Write a short explanation for each of the following analog VO module specifications a. Channels per module b. Input current/voltage range(s) c. Output current/voltage range(s) d. Input protection e. Resolution f. Input impedance and capacitance Compare the memory storage characteristics of volatile and nonvolatile memory elements. 48. 38. 49. What information is normally stored in the ROM 50. 51. 52. What are the advantages of a processor that utili memory of a PLC? What information is normally stored in the RAM memory of a PLC? What information is normally stored in an EEPROM memory module? a flash memory card? 39. Compare the function of the CPU and memory sec- 53. List three functions of a PLC programming term 40. With reference to the PLC chassis power supply: 54. Give one advantage and one limitation to the us tions of a PLC processor. nal device. a. What conversion of power takes place within the power supply circuit? b. Explain the term hold-up time as it applies to the hand-held programming devices What is required for a personal computer to be as a PLC programming terminal? power supply Explain the purpose of a redundant PLC processor. Describe three typical modes of operation that can be selected by the keyswitch of a processor. State five other functions, in addition to simple logic processing, that PLC processors are capable of performing 55. 56. List four important capabilities of PLC progra 57 58. 41. 42. 43. ming software. How many programs can a PLC have stored i memory at any one time? Outline four functions that an HMI interface . can be configured to perform. PLC Hardware Components Chapter 2 ?CHAPTER 2 REVIEW QUESTIONS 21. With reference to discrete output module What is the function of a PLC input interface module? 1. ratings: for a typi a. What is the maximum current rating f What is the function of a PLC output interface module? 2. 120 VAC output module? b. Explain one method of handling out 3. Define the term logical rack larger current requirements. What electronic element can be used as the sw ing device for DC discrete output modules? 23. A discrete relay type output module can be use 4. With reference to a PLC rack 22. ' a. What is a remote rack? b. Why are remote racks used? How does the processor identify the location of a specific input or output device to 5. switch either AC or DC load devices. Why? 24. With reference to sourcing and sinking I/O 6. List the three basic elements of rack/slot-based addressing. a. What current relationship are the terms sourcin 7. Compare bit level and word level addressing and sinking used to describe? 8. In what way does tag-based addressing differ from b. If an LVO module is specified as a current rack/slot-based addressin type, then which type of field device (sinking or 9. 10. What type of VO modules have both inputs and 11. In addition field sourcing) it is electrically compatible with? 25. Compare discrete and analog IO modules with What do PC-based control systems use to interface with field devices? outputs connected to them? respect to the type of input or output devices with which they can be used. on to feld devices what other connections 26. Explain the function of the analog-to-digital (A/D) are made to a PLC module? Most PLC modules use plug-in wiring terminal strips. Why? What are the advantage and the disadvantage of using high-density modules? 12. converter circuit used in analog input modules. 27. Explain the function of the digital-to-analog (D/A) 28. 29. 30. converter circuit used in analog output modules. Name the two general sensing classifications for analog input modules List five common physical quantities measured by a PLC analog input module What type of cable is used when connecting a ther- mocouple to a voltage sensing analog input mod- ule? Why? 13. 14. With reference to PLC discrete input modules: a. What types of field input devices are suitable for use with them? b. List three examples of discrete input devices 15. With reference to PLC discrete output modules: a. What types of field output devices are suitable Explain the difference between a unipolar and bi- polar analog input module. fied as 0.3 mV. What does this tell you? sensing input modules be supplied? by a PLC analog output module. for use with them? 31. b. List three examples of discrete output devices.3 16. Explain the function of the backplane of a PLC 17. What is the function of the optical isolator circuit 18. Name the two distinct sections of an IVO module 32. The resolution of an analog input channel is speci- 33. In what two ways can the loop power for current 34. List three field devices that are commonly controlled 35. State one application for each of the following spe- rac used in discrete /O module circuits? 19. List four tasks performed by a discrete input Lul 20. cial I/O modules: What electronic element can be used as the switch ing device for a 120 VAC discrete output interface a. High-speed counter module b. Thumbwheel module module? c. TTL module