PROGRAMMABLE LOGIC CONTROLLERS
5TH EDITION EXAM STUDY GUIDE
2026/2027 ACCURATE QUESTIONS WITH
CORRECT DETAILED SOLUTIONS ||
100% GUARANTEED PASS
<NEWEST VERSION>
1. Programmable Logic Controllers - ANSWER ✔ Used to control Robots,
Electric motors, conveyors.
2. First PLC introduction - ANSWER ✔ Introduced in the Automotive
industry.
3. PLC replacement - ANSWER ✔ Designed to replace Electromechanical
Relay panels.
4. What are the main components of a PLC? - ANSWER ✔ Power supply,
Central Processing Unit (CPU), Programming terminal, I/O Rack, Input
modules, Output modules, Internal relays, Timers, and Counters.
5. What is the function of the power supply in a PLC? - ANSWER ✔ It
lowers incoming AC voltage, rectifies it to direct current, and regulates it to
ensure stable operation.
6. What does the CPU of a PLC do? - ANSWER ✔ It performs all logic
functions and contains the microprocessor chip and related integrated
circuits.
7. What is the purpose of a programming terminal in a PLC? - ANSWER ✔ It
is used to program the CPU and can also troubleshoot circuits while in
operation.
,8. What is the role of the I/O Rack in a PLC? - ANSWER ✔ It connects the
CPU to the outside world, containing input modules that carry information
to the CPU and output modules that send instructions from the CPU.
9. How does an input module function in a PLC? - ANSWER ✔ It carries
information from control sensor devices to the CPU and uses opto-isolation
to protect the CPU from voltage spikes.
10.What is the function of an output module in a PLC? - ANSWER ✔ It
connects the CPU to the load and provides line isolation between the CPU
and the external circuit.
11.What are internal relays in a PLC? - ANSWER ✔ They perform actual
logic functions within the PLC and can be programmed as normally open or
normally closed contacts.
12.What are timers and counters in a PLC? - ANSWER ✔ They are internal
relays programmed into logic for timing functions, generally programmed in
0.1-second intervals.
13.What is an off-delay circuit in a PLC? - ANSWER ✔ It allows an on-delay
timer to perform an off-delay function by keeping contacts energized for a
period after de-energizing the timer coil.
14.What is the significance of the programming terminal's display? - ANSWER
✔ It shows the program display and allows observation of circuit
operation, which can be done through handheld devices or laptops.
15.Volatile memory elements can be classified as those that: - ANSWER ✔
do not retain stored information when the power is removed. (p.36)
16.An analog input or output is a signal that varies continuously within a certain
range. (True/False) - ANSWER ✔ True (p.29)
17.I/O modules are designed to plug into a slot or connector. (True/False) -
ANSWER ✔ True (p.20)
,18.Most input modules have blown fuse indicators. (True/False) - ANSWER
✔ False (p.19)
19.Optical isolation used in I/O modules helps to reduce the effects of electrical
noise. (True/False) - ANSWER ✔ True (p.24)
20.I/O modules are keyed to prevent unauthorized personnel from removing
them from the I/O rack. (True/False) - ANSWER ✔ False (p.20)
21.The maximum current rating for the individual outputs of an AC output
module is usually in the 20 to 30 ampere range. (True/False) - ANSWER
✔ False (p.27)
22.A thermocouple would be classified as an analog input sensing device.
(True/False) - ANSWER ✔ True (p.28)
23.Shielded twisted pair cable is used for connecting to thermocouple inputs to
reduce unwanted electrical noise. (True/False) - ANSWER ✔ True (p.28)
24.Electrical noise usually causes permanent operating errors. (True/False) -
ANSWER ✔ False (p.24)
25.The processor may perform functions such as timing, counting, and
comparing in addition to logic processing. (True/False) - ANSWER ✔
True (p.34 - 35)
26.Memory is where the control plan is held or stored in the controller.
(True/False) - ANSWER ✔ True
27.A volatile memory will lose its programmed contents if operating power is
lost. (True/False) - ANSWER ✔ True (p.36)
28.A nonvolatile memory will retain its programmed contents if operating
power is lost. (True/False) - ANSWER ✔ True (p. 36)
29.RAM memory is nonvolatile. (True/False) - ANSWER ✔ False (p.36)
, 30.Information stored in a RAM memory location can be written into or read
from. (True/False) - ANSWER ✔ True (p.36)
31.When a new program is loaded into a PLC's memory, the old program that
was stored in the same locations is over - written and essentially erased.
(True/False) - ANSWER ✔ True (p.37)
32.Most PLC programming software will allow you to develop programs on
another manufacturer's PLC. (True/False) - ANSWER ✔ False (p.38)
33.Analog signals can have only two states. (True/False) - ANSWER ✔ False
(p.27)
34.A modular PLC that has room for several I/O modules, is capable of being
customized for a particular application. (True/False) - ANSWER ✔ True
(p.18)
35.I/O modules are normally installed or removed while the PLC is powered.
(True/False) - ANSWER ✔ True (p.20)
36.A redundant PLC system is configured using two processors. (True/False) -
ANSWER ✔ True (p.34)
37.Most PLC electronic components are not sensitive to electrostatic discharge.
(True/False) - ANSWER ✔ False (p.35)
38.One advantage of discrete relay contact output modules is that they can be
used with AC or DC devices. (True/False) - ANSWER ✔ True (p.26)
39.Discrete means that each input or output has two states: true (on) or false
(off). (True/False) - ANSWER ✔ True (p.22)
40.The sum of the backplane current drawn for all modules in a chassis is used
to select the appropriate chassis power supply rating. (True/False) -
ANSWER ✔ True (p.34)
5TH EDITION EXAM STUDY GUIDE
2026/2027 ACCURATE QUESTIONS WITH
CORRECT DETAILED SOLUTIONS ||
100% GUARANTEED PASS
<NEWEST VERSION>
1. Programmable Logic Controllers - ANSWER ✔ Used to control Robots,
Electric motors, conveyors.
2. First PLC introduction - ANSWER ✔ Introduced in the Automotive
industry.
3. PLC replacement - ANSWER ✔ Designed to replace Electromechanical
Relay panels.
4. What are the main components of a PLC? - ANSWER ✔ Power supply,
Central Processing Unit (CPU), Programming terminal, I/O Rack, Input
modules, Output modules, Internal relays, Timers, and Counters.
5. What is the function of the power supply in a PLC? - ANSWER ✔ It
lowers incoming AC voltage, rectifies it to direct current, and regulates it to
ensure stable operation.
6. What does the CPU of a PLC do? - ANSWER ✔ It performs all logic
functions and contains the microprocessor chip and related integrated
circuits.
7. What is the purpose of a programming terminal in a PLC? - ANSWER ✔ It
is used to program the CPU and can also troubleshoot circuits while in
operation.
,8. What is the role of the I/O Rack in a PLC? - ANSWER ✔ It connects the
CPU to the outside world, containing input modules that carry information
to the CPU and output modules that send instructions from the CPU.
9. How does an input module function in a PLC? - ANSWER ✔ It carries
information from control sensor devices to the CPU and uses opto-isolation
to protect the CPU from voltage spikes.
10.What is the function of an output module in a PLC? - ANSWER ✔ It
connects the CPU to the load and provides line isolation between the CPU
and the external circuit.
11.What are internal relays in a PLC? - ANSWER ✔ They perform actual
logic functions within the PLC and can be programmed as normally open or
normally closed contacts.
12.What are timers and counters in a PLC? - ANSWER ✔ They are internal
relays programmed into logic for timing functions, generally programmed in
0.1-second intervals.
13.What is an off-delay circuit in a PLC? - ANSWER ✔ It allows an on-delay
timer to perform an off-delay function by keeping contacts energized for a
period after de-energizing the timer coil.
14.What is the significance of the programming terminal's display? - ANSWER
✔ It shows the program display and allows observation of circuit
operation, which can be done through handheld devices or laptops.
15.Volatile memory elements can be classified as those that: - ANSWER ✔
do not retain stored information when the power is removed. (p.36)
16.An analog input or output is a signal that varies continuously within a certain
range. (True/False) - ANSWER ✔ True (p.29)
17.I/O modules are designed to plug into a slot or connector. (True/False) -
ANSWER ✔ True (p.20)
,18.Most input modules have blown fuse indicators. (True/False) - ANSWER
✔ False (p.19)
19.Optical isolation used in I/O modules helps to reduce the effects of electrical
noise. (True/False) - ANSWER ✔ True (p.24)
20.I/O modules are keyed to prevent unauthorized personnel from removing
them from the I/O rack. (True/False) - ANSWER ✔ False (p.20)
21.The maximum current rating for the individual outputs of an AC output
module is usually in the 20 to 30 ampere range. (True/False) - ANSWER
✔ False (p.27)
22.A thermocouple would be classified as an analog input sensing device.
(True/False) - ANSWER ✔ True (p.28)
23.Shielded twisted pair cable is used for connecting to thermocouple inputs to
reduce unwanted electrical noise. (True/False) - ANSWER ✔ True (p.28)
24.Electrical noise usually causes permanent operating errors. (True/False) -
ANSWER ✔ False (p.24)
25.The processor may perform functions such as timing, counting, and
comparing in addition to logic processing. (True/False) - ANSWER ✔
True (p.34 - 35)
26.Memory is where the control plan is held or stored in the controller.
(True/False) - ANSWER ✔ True
27.A volatile memory will lose its programmed contents if operating power is
lost. (True/False) - ANSWER ✔ True (p.36)
28.A nonvolatile memory will retain its programmed contents if operating
power is lost. (True/False) - ANSWER ✔ True (p. 36)
29.RAM memory is nonvolatile. (True/False) - ANSWER ✔ False (p.36)
, 30.Information stored in a RAM memory location can be written into or read
from. (True/False) - ANSWER ✔ True (p.36)
31.When a new program is loaded into a PLC's memory, the old program that
was stored in the same locations is over - written and essentially erased.
(True/False) - ANSWER ✔ True (p.37)
32.Most PLC programming software will allow you to develop programs on
another manufacturer's PLC. (True/False) - ANSWER ✔ False (p.38)
33.Analog signals can have only two states. (True/False) - ANSWER ✔ False
(p.27)
34.A modular PLC that has room for several I/O modules, is capable of being
customized for a particular application. (True/False) - ANSWER ✔ True
(p.18)
35.I/O modules are normally installed or removed while the PLC is powered.
(True/False) - ANSWER ✔ True (p.20)
36.A redundant PLC system is configured using two processors. (True/False) -
ANSWER ✔ True (p.34)
37.Most PLC electronic components are not sensitive to electrostatic discharge.
(True/False) - ANSWER ✔ False (p.35)
38.One advantage of discrete relay contact output modules is that they can be
used with AC or DC devices. (True/False) - ANSWER ✔ True (p.26)
39.Discrete means that each input or output has two states: true (on) or false
(off). (True/False) - ANSWER ✔ True (p.22)
40.The sum of the backplane current drawn for all modules in a chassis is used
to select the appropriate chassis power supply rating. (True/False) -
ANSWER ✔ True (p.34)
