Question

. What is a programmable logic controller (PLC)?12. The , Identify four tasks in addition to relay switching operations that PLCs are capable performing. 3. List six distinct advantages that PLCs offer over controller operates in real time. What does this mean? of performing 13. Answer the following with reference to the f conventional relay-based control systems. control PLC ladder logic diagram of Figure 1-21 this etary PLC architecture. 5. State two ways in which LVO is incorporated into 4, Explain the differences between open and propri- a. What do the individual symbols represent? b. What do the numbers represent? e. What field device is the number 1/2 identified the PLC 6. Describe how the L/O modules connect to the pro- with? d. What field device is the number O/1 identified cessor in a modular-type PLC configuration. 7. with? Explain the main function of each of the following e. What two conditions will provide a continuous path from left to right across the rung f. Describe the sequence of operation of the major components of a PLC: a. Processor module (CPU) controller for one scan of the program. Compare the method by which the process operation is changed in a relay-based system to the b. L/O modules c. Programming device 14. d. Power supply module method used for a PLC-based system. Compare the PLC and PC with regard to: a. Physical hardware differences b. Operating environment c. Method of programming d. Execution of program What two categories of software written and run on PCs are used in conjunction with PLCs? What is a programmable automation controller (PAC)? List four criteria by which PLCs are categorized. t common types of PLC pro- 15. 9. Explain the terms program and programming lan- 10. What is the standard programming language used 11. Answer the following with reference to the process gramming devices? guage as they apply to a PLC. with PLCs? 16. control relay ladder diagram of Figure 1-18 of this chapter: a. When do the pressure switch contacts close? b. When do the temperature switch contacts close? c. How are the pressure and temperature switches 17. 18. 19. Compare the single-ended, multitask, and control management types of PLC applications. What is the memory capacity, expressed in bits, for a PLC that uses 16-bit words and has an 8 K word capacity List five factors affecting the memory size needed for a particular PLC installation What does the instruction set for a particular PLC refer to? connected with respect to each other? d. Describe the two conditions under which the 20. motor starter coil will become energized. e. What is the approximate value of the voltage 21. op across each of the following when their contacts are open? (1) Pressure switch (2) Temperature switch (3) Manual pushbutton 22. CHAPTER 1 PROBLEMS 2. Given two single-pole switches, write a program tha Given two single-pole switches, write a program that will turn on an output when both switch A and switch B are closed will turn on an output when either switch A or swit B is closed.

Answer 1