COMPLETE SOLUTION MANUAL PROGRAMMABLE LOGIC
CONTROLLERS 5TH EDITION PETRUZELLA 250 QUESTIONS AND
ANSWERS WITH RATIONALES CHAPTER 1 TO 15 2026/2027 || PLC
FUNDAMENTALS & INDUSTRIAL AUTOMATION || LOGIC
SEQUENCING & PROGRAMMING || TROUBLESHOOTING &
APPLICATIONS || DETAILED EXPLANATIONS WITH RATIONALES ||
HIGH-YIELD STUDY GUIDE || COMPLETE REVIEW MATERIAL ||
GRADED A+
PLCs were originally designed as replacements for
a. microcomputers
b. relay control panels
c. analog controllers
d. digital controllers - CORRECT ANSWER -b
Basically, the function of a PLC is to a. amplify various weak signal sources
b. control a high-voltage output with a low-voltage input
c. control the speed of motors
d. make logical decisions and control outputs based on them - CORRECT
ANSWER -d
Modifying relay-type process control circuits usually involves changing the
a. circuit wiring
b. input circuit modules
c. output circuit modules
d. circuit operating voltage levels - CORRECT ANSWER -a
Which of the following is not an advantage that PLCs offer over the
conventional relay-type of control system?
a. Smaller size
,b. Less expensive
c. Higher current capacity
d. More reliable - CORRECT ANSWER -c
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 - CORRECT ANSWER -d
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 - CORRECT ANSWER -a
PLC proprietary architecture
a. is the opposite to open architecture
b. makes it more difficult to connect to decides made by other PLC
manufacturers
c. does not allow programs to be interchanged between different PLC
manufacturers
d. all of the above - CORRECT ANSWER -a
The output interface module connects to
,a. sensing devices such as switches or pushbuttons
b. load devices such as lamps and solenoids
c. a programming device such as a computer
d. all of the above - CORRECT ANSWER -b
Field or real-world devices refer to
a. input devices only
b. output devices only
c. load devices only
d. all devices that are physically wired to the PLC - CORRECT ANSWER -
d
The power required to operate the logic circuits of the processor unit is typically
a. low-voltage AC
b. high-voltage AC
c. low-voltage DC
d. high-voltage DC - CORRECT ANSWER -c
The control plan stored in the PLC is called
a. a program
b. a Boolean ladder
c. FORTRAN
d. a microprocessor - CORRECT ANSWER -a
The programming device
a. is used to enter the program into the memory of the processor
b. is commonly a personal computer
, c. can be a handheld device
d. all of the above - CORRECT ANSWER -d
The programming device must be connected to the controller
a. at all times
b. when entering a program
c. when monitoring a program
d. both b and c - CORRECT ANSWER -d
At the start of the PLC scan the
a. status of all inputs is read
b. status of all outputs is updated
c. program is executed
d. diagnostics and communications tasks are executed - CORRECT
ANSWER -a
The scan time is the time required
a. to record the status of all input devices
b. to record the status of all output devices
c. to execute one cycle of the total program
d. for the information to pass from input to output - CORRECT ANSWER -
c
Unlike personal computers, PLCs are
a. equipped with input and output modules
b. equipped with a control programming language
c. designed for the industrial environment
CONTROLLERS 5TH EDITION PETRUZELLA 250 QUESTIONS AND
ANSWERS WITH RATIONALES CHAPTER 1 TO 15 2026/2027 || PLC
FUNDAMENTALS & INDUSTRIAL AUTOMATION || LOGIC
SEQUENCING & PROGRAMMING || TROUBLESHOOTING &
APPLICATIONS || DETAILED EXPLANATIONS WITH RATIONALES ||
HIGH-YIELD STUDY GUIDE || COMPLETE REVIEW MATERIAL ||
GRADED A+
PLCs were originally designed as replacements for
a. microcomputers
b. relay control panels
c. analog controllers
d. digital controllers - CORRECT ANSWER -b
Basically, the function of a PLC is to a. amplify various weak signal sources
b. control a high-voltage output with a low-voltage input
c. control the speed of motors
d. make logical decisions and control outputs based on them - CORRECT
ANSWER -d
Modifying relay-type process control circuits usually involves changing the
a. circuit wiring
b. input circuit modules
c. output circuit modules
d. circuit operating voltage levels - CORRECT ANSWER -a
Which of the following is not an advantage that PLCs offer over the
conventional relay-type of control system?
a. Smaller size
,b. Less expensive
c. Higher current capacity
d. More reliable - CORRECT ANSWER -c
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 - CORRECT ANSWER -d
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 - CORRECT ANSWER -a
PLC proprietary architecture
a. is the opposite to open architecture
b. makes it more difficult to connect to decides made by other PLC
manufacturers
c. does not allow programs to be interchanged between different PLC
manufacturers
d. all of the above - CORRECT ANSWER -a
The output interface module connects to
,a. sensing devices such as switches or pushbuttons
b. load devices such as lamps and solenoids
c. a programming device such as a computer
d. all of the above - CORRECT ANSWER -b
Field or real-world devices refer to
a. input devices only
b. output devices only
c. load devices only
d. all devices that are physically wired to the PLC - CORRECT ANSWER -
d
The power required to operate the logic circuits of the processor unit is typically
a. low-voltage AC
b. high-voltage AC
c. low-voltage DC
d. high-voltage DC - CORRECT ANSWER -c
The control plan stored in the PLC is called
a. a program
b. a Boolean ladder
c. FORTRAN
d. a microprocessor - CORRECT ANSWER -a
The programming device
a. is used to enter the program into the memory of the processor
b. is commonly a personal computer
, c. can be a handheld device
d. all of the above - CORRECT ANSWER -d
The programming device must be connected to the controller
a. at all times
b. when entering a program
c. when monitoring a program
d. both b and c - CORRECT ANSWER -d
At the start of the PLC scan the
a. status of all inputs is read
b. status of all outputs is updated
c. program is executed
d. diagnostics and communications tasks are executed - CORRECT
ANSWER -a
The scan time is the time required
a. to record the status of all input devices
b. to record the status of all output devices
c. to execute one cycle of the total program
d. for the information to pass from input to output - CORRECT ANSWER -
c
Unlike personal computers, PLCs are
a. equipped with input and output modules
b. equipped with a control programming language
c. designed for the industrial environment
