Name: ________________________ Class: ___________________ Date: __________ ID: A 1 MECH 1500 Midterm Review True/False Indicate whether the statement is true or false. ____ 1. Normally, a binary 1 represents the presence of a signal, while a binary 0 represents the absence of a signal. ____ 2. All gates are devices that have one input with which they perform logic decisions and produce a result at one or more of their outputs. ____ 3. All inputs to an AND gate must be 1 to produce a 1 output. ____ 4. All inputs to a NAND gate must be 1 to produce a 1 output. ____ 5. Only one input to an OR gate must be 1 to produce a 1 output. ____ 6. All inputs to a NOR gate must be 1 to produce a 1 output. ____ 7. Inverting the output of an OR gate will result in creating a NOR gate. ____ 8. The AND function, implemented using switches, will mean switches connected in parallel. ____ 9. A two input OR function, expressed as a Boolean equation, would be Y= AB. ____ 10. Hardwired logic refers to logic control functions determined by the way devices are interconnected. ____ 11. Hardwired logic can be implemented using relays and relay schematics. ____ 12. Hardwired logic is fixed and is changeable only by altering the way devices are connected. ____ 13. Programmable control is based on logic functions that are programmable and easily changed.
Transcript
Name: ________________________ Class: ___________________ Date: __________ ID: A
1
MECH 1500 Midterm Review
True/FalseIndicate whether the statement is true or false.
____ 1. Normally, a binary 1 represents the presence of a signal, while a binary 0 represents
the absence of a signal.
____ 2. All gates are devices that have one input with which they perform logic decisions and
produce a result at one or more of their outputs.
____ 3. All inputs to an AND gate must be 1 to produce a 1 output.
____ 4. All inputs to a NAND gate must be 1 to produce a 1 output.
____ 5. Only one input to an OR gate must be 1 to produce a 1 output.
____ 6. All inputs to a NOR gate must be 1 to produce a 1 output.
____ 7. Inverting the output of an OR gate will result in creating a NOR gate.
____ 8. The AND function, implemented using switches, will mean switches connected in
parallel.
____ 9. A two input OR function, expressed as a Boolean equation, would be
Y= AB.
____ 10. Hardwired logic refers to logic control functions determined by the way devices are
interconnected.
____ 11. Hardwired logic can be implemented using relays and relay schematics.
____ 12. Hardwired logic is fixed and is changeable only by altering the way devices are
connected.
____ 13. Programmable control is based on logic functions that are programmable and easily
changed.
Name: ________________________ ID: A
2
____ 14. There is no difference between a relay schematic and a ladder logic program.
____ 15. On some PLCs, only one output is allowed per ladder logic rung.
____ 16. One of the most common PLC programming languages is ladder logic.
____ 17. Ladder logic is a graphical representation of a user program.
____ 18. The decimal system uses the number 9 as its base.
____ 19. All digital computing devices perform operations in binary.
____ 20. The base of a number system determines the total number of unique symbols used by
that system.
____ 21. In any number system, the position of a digit that represents part of the number has a
weighted value associated with it.
____ 22. Usually a group of 8 bits is a byte, and a group of one or more bytes is a word.
____ 23. To express a number in binary requires fewer digits than in the decimal system.
____ 24. The octal number system consists of digits 0, 1, 2, 3, 4, 5, 6, and 7. There are no 8's or
9's.
____ 25. The hexadecimal number system consists of 16 digits including the numbers 0 through
9 and letters A through F.
____ 26. In the Gray code there is a maximum of one bit change between two consecutive
numbers.
____ 27. The radix of a number system is the same as the base.
____ 28. Binary number systems use positive and negative symbols to represent the polarity of
a number.
Name: ________________________ ID: A
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____ 29. RAM memory is nonvolatile.
____ 30. Digital modules are also called discrete modules.
____ 31. The number and type of I/Os cannot be changed in a fixed PLC.
____ 32. The scan time is the time required for one complete execution of the user program.
____ 33. A personal computer communicates with the PLC processor via a serial or parallel
data communications link.
____ 34. The programmable controller operates in real time.
Multiple ChoiceIdentify the choice that best completes the statement or answers the question.
____ 35. A gate is a device that:
a. allows current flow in one direction only.
b. changes alternating current to direct current.
c. performs a logical decision based on its inputs.
d. performs a logical decision based on its outputs.
____ 36. The basic rule for an AND gate is:
a. if all inputs are 1, the output will be 1.
b. if all inputs are 1, the output will be 0.
c. if all inputs are 0, the output will be 1.
d. both a and b.
____ 37. The basic rule for an OR gate is:
a. if one or more inputs are 1, the output is 1.
b. if one or more inputs are 1, output is 0.
c. if one or more inputs are 0, the output is 1.
d. both band c.
Name: ________________________ ID: A
4
____ 38. The NOT function can be thought of as:
a. a FALSE-to-TRUE converter. c. an inverter.
b. a changer of states. d. all of these.
____ 39. The logic symbol shown is that of the:
a. AND function. c. NOT function.
b. OR function. d. NAND function.
____ 40. The Boolean equation for the logic symbol is:
a. Y= A + B c. Y= A • Bb. Y= AB d. either b or c.
____ 41. The logic symbol drawn is that of the:
a. AND function. c. NOT function.
b. OR function. d. NOR function.
____ 42. The Boolean equation for the logic symbol is:
a. Y= A+B+C c. Y= (AB)+Cb. Y = ABC d. Y = (A –B)C
Name: ________________________ ID: A
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____ 43. With reference to the logic circuit, the output Y will be at a logic 1 when:
a. inputs A and B are logic 1.
b. input A or B is logic 1.
c. input A is at logic 1 and input B is at logic 0.
d. input A is at logic 0 and input B is at logic 1.
____ 44. The logic symbol drawn in that of the:
a. AND function. c. NOR function.
b. OR function. d. NAND function.
____ 45. The logic symbol drawn is that of the:
a. NOT function. c) NAND function.
b. NOR function. d) OR function.
____ 46. The Boolean expression for the logic circuit drawn is:
a. Y = ABC c. Y = (A + B)Cb. Y=A+B+C d. Y=AB+C
Name: ________________________ ID: A
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____ 47. The Boolean expression for the logic circuit drawn in is:
a. Y = (A B)(CD) c.
b. d. Y= ABC + D
____ 48. The Boolean expression for the logic circuit is:
a. c.
b. d.
Name: ________________________ ID: A
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____ 49. Which of the hardwired relay schematics of is being implemented by the PLC
program shown?
a. (a) c. (c)b. (b) d. (d)
____ 50. A OR gate operates on the same principle as:
a. a series circuit. c. a series-parallel circuit.
b. a parallel circuit. d. none of these.
____ 51. A NOR gate is:
a. an AND gate with an inverter connected to the output.
b. an OR gate with an inverter connected to the output.
c. equivalent to a series circuit.
d. equivalent to a parallel circuit.
____ 52. The number 12 is:
a. 12 in any number system. c. 12 in binary.
b. 12 in decimal. d. all of the above.
Name: ________________________ ID: A
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____ 53. The octal number 153 would be written in binary as:
a. 011 101 001. c. 011 111 101.
b. 001 101 011. d. 010 100 011.
____ 54. The hexadecimal number 2D9 would be written in binary as:
a. 0010 1101 1001. c. 1100 1111 0010.
b. 1001 1011 0010. d. 0010 1011 1001.
____ 55. One byte of the data shown is represented by:
a. No. 1 c. No. 3b. No. 2 d. No. 4
____ 56. A ____ is an example of an actuator that could be controlled by a discrete output from
a PLC.
a. pushbutton c. limit switch
b. motor starter d. all of these
____ 57. A/An ____ input or output is a continuously variable signal within a designated range.
a. discrete c. BCD
b. digital d. analog
____ 58. Which of the following input field devices would most likely be used with an analog
interface input module?
a. Pushbutton c. Selector switch
b. Limit switch d. Thermocouple
Name: ________________________ ID: A
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____ 59. The schematic diagram shown is that of a(n):
a. discrete output module. c. discrete input module.
b. analog output module. d. analog input module.
____ 60. The purpose of the filter section is to:
a. aid in fault diagnosis.
b. set the minimum level of voltage that can be detected.
c. protect against electrical noise interference.
d. separate the higher line voltage from the logic circuits .
Name: ________________________ ID: A
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____ 61. The purpose of the zener diode (ZD) is to:
a. aid in fault diagnosis.
b. set the minimum level of voltage that can be detected.
c. protect against electrical noise interference.
d. separate the higher line voltage from the logic circuits .
____ 62. High-density I/O modules:
a. may have up to 64 inputs or outputs per module.
b. require more space.
c. can handle greater amounts of current per output.
d. all of the above.
____ 63. Discrete I/O modules can be classified as:
a. bit oriented. c. processor oriented.
b. word oriented. d. power supply oriented.
____ 64. Batteries are used in a PLC's processor to
a. maintain data in volatile
memory when line power is
removed from the processor.
c. maintain data in nonvolatile
memory when line power is
removed from the processor.
b. operate the status lights LEDs. d. maintain outputs through a
power failure.
Name: ________________________ ID: A
11
____ 65. PLCs were originally designed as replacements for:
a. microcomputers. c. analog controllers.
b. relay control panels. d. digital controllers.
____ 66. Which of the following is not an advantage that PLCs
offer over the conventional relay-type of control system?
a. Smaller size c. Higher current capacity
b. Less expensive d. More reliable
____ 67. The main difference between a PLC and relay control system is that:
a. different types of input devices are used.
b. different types of output devices are used.
c. different input and output voltage levels are used.
d. one uses hardwired relay control logic and the other uses programmed
instructions.
____ 68. The central processing unit:
a. looks at the inputs, makes the decisions based on the program,
and sets the outputs.
b. looks at the outputs, makes the decisions based on the program, and
sets the inputs.
c. serves only to store the program in memory.
d. serves only to supply power to the backplane.
____ 69. The control plan stored in the PLC is called:
a. a program. c. FORTRAN.
b. a Boolean ladder. d. a microprocessor.
____ 70. A human machine interface (HMI)
a. allows the user to monitor a process.
b. allows the user to control a process.
c. can provide a graphical representation of a process .
d. all of the above.
Name: ________________________ ID: A
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____ 71. The voltage that would be present between the DC common and terminal 4 with the
pushbutton closed would be approximately:
a. 0 volts. c. 12 volts.
b. 6 volts. d. 24 volts.
____ 72. The devices connected to the terminals would be classified as:
a. field input devices. c. field output devices.
b. internal input instructions. d. internal output instructions
Name: ________________________ ID: A
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____ 73. The diagram shown is that of a
a. hardwired relay schematic. c. input module schematic.
b. ladder logic program. d. output module schematic.
____ 74. For there to be is a continuous logic path from left to right across the rung:
a. I/1, 1/2, and 1/3 must all be at logic 1.
b. I/1, 1/2, and 1/3 must all be at logic 0.
c. I/1 and 1/2 or 1/3 must be at logic 1.
d. I/1 and 1/2 or 1/3 will be at logic 0.
Short Answer
75. Convert the binary number to a decimal number:1111110
Name: ________________________ ID: A
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76. Convert the decimal number to a binary number:20
77. Convert the Octal number to a binary number:74
78. What is the 1s complement of 1001101?
79. Simplify, answer must be in binary.100 +101
80. Simplify, answer must be in binary.1101 - 0101
ID: A
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MECH 1500 Midterm ReviewAnswer Section
TRUE/FALSE
1. ANS: T PTS: 1 2. ANS: F PTS: 1 3. ANS: T PTS: 1 4. ANS: F PTS: 1 5. ANS: T PTS: 1 6. ANS: F PTS: 1 7. ANS: T PTS: 1 8. ANS: F PTS: 1 9. ANS: F PTS: 1 10. ANS: T PTS: 1 11. ANS: T PTS: 1 12. ANS: T PTS: 1 13. ANS: T PTS: 1 14. ANS: F PTS: 1 15. ANS: T PTS: 1 16. ANS: T PTS: 1 17. ANS: T PTS: 1 18. ANS: F PTS: 1 19. ANS: T PTS: 1 20. ANS: T PTS: 1 21. ANS: T PTS: 1 22. ANS: T PTS: 1 23. ANS: F PTS: 1 24. ANS: T PTS: 1 25. ANS: T PTS: 1 26. ANS: T PTS: 1 27. ANS: T PTS: 1 28. ANS: F PTS: 1 29. ANS: T PTS: 1 30. ANS: T PTS: 1 31. ANS: T PTS: 1 32. ANS: T PTS: 1 33. ANS: T PTS: 1 34. ANS: T PTS: 1
MULTIPLE CHOICE
35. ANS: C PTS: 1 36. ANS: A PTS: 1 37. ANS: A PTS: 1
ID: A
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38. ANS: D PTS: 1 39. ANS: B PTS: 1 40. ANS: A PTS: 1 41. ANS: A PTS: 1 42. ANS: B PTS: 1 43. ANS: C PTS: 1 44. ANS: D PTS: 1 45. ANS: A PTS: 1 46. ANS: D PTS: 1 47. ANS: B PTS: 1 48. ANS: C PTS: 1 49. ANS: B PTS: 1 50. ANS: B PTS: 1 51. ANS: B PTS: 1 52. ANS: B PTS: 1 53. ANS: B PTS: 1 54. ANS: A PTS: 1 55. ANS: A PTS: 1 56. ANS: B PTS: 1 57. ANS: D PTS: 1 58. ANS: D PTS: 1 59. ANS: C PTS: 1 60. ANS: C PTS: 1 61. ANS: B PTS: 1 62. ANS: A PTS: 1 63. ANS: A PTS: 1 64. ANS: A PTS: 1 65. ANS: B PTS: 1 66. ANS: C PTS: 1 67. ANS: D PTS: 1 68. ANS: A PTS: 1 69. ANS: A PTS: 1 70. ANS: D PTS: 1 71. ANS: D PTS: 1 72. ANS: A PTS: 1 73. ANS: A PTS: 1 74. ANS: C PTS: 1
