AZ L-60 Controls & Automation Contractor
Exam Questions and Correct Answers (Verified
Answers) Plus Rationale 2027 Q&A| Instant
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1. What is the primary purpose of a programmable logic controller
(PLC) in an automated control system?
a. To provide mechanical support for motors
b. To store electrical energy
c. To monitor inputs, execute programmed logic, and control outputs
d. To increase the voltage supplied to equipment
Rationale: A PLC receives information from input devices such as
sensors and switches, processes that information according to its
program, and commands output devices such as relays, valves, and
motors. This makes it a central component of many industrial
automation systems.
, 2. Which device is commonly used to detect the presence or
position of a physical object without making direct contact?
a. Float switch
b. Push-button switch
c. Proximity sensor
d. Circuit breaker
Rationale: A proximity sensor detects an object within a specified
sensing range without requiring physical contact. Depending on its
design, it may detect metal, magnetic fields, capacitance, or other
characteristics.
3. In a control circuit, what is the primary function of a relay?
a. Convert AC voltage into hydraulic pressure
b. Use a control signal to switch another electrical circuit
c. Measure pipe pressure
d. Store a PLC program permanently
Rationale: A relay uses an electrically operated coil to open or close
contacts. This allows a relatively low-power control signal to operate
a separate circuit, often providing isolation between control and load
circuits.
, 4. What does the term “normally open” (NO) mean when describing
a control contact?
a. The contact is always energized
b. The contact is permanently closed
c. The contact is open when the controlling device is in its normal, de-
energized condition
d. The contact cannot be operated manually
Rationale: A normally open contact remains open in its normal state
and closes when the associated device or coil operates. NO contacts
are commonly used for start commands and signaling functions.
5. Which instrument is used to measure electrical resistance?
a. Ammeter
b. Voltmeter
c. Wattmeter
d. Ohmmeter
Rationale: An ohmmeter measures resistance in ohms. Most modern
digital multimeters combine resistance, voltage, and current
measurement functions in one instrument.
6. What is the purpose of an emergency-stop circuit?
, a. Increase motor speed during an overload
b. Automatically restart equipment after a power failure
c. Bring hazardous equipment to a safe state during an emergency
d. Increase the operating temperature of a process
Rationale: Emergency-stop functions are intended to rapidly remove
or control hazardous energy or motion when an emergency occurs.
They are safety functions and should be designed so that a fault does
not defeat the intended protective action.
7. Which type of sensor is commonly used to measure temperature
electronically?
a. Inductive proximity sensor
b. Photoelectric sensor
c. RTD
d. Limit switch
Rationale: A resistance temperature detector (RTD) measures
temperature by using the predictable change in electrical resistance of
a sensing element, commonly platinum, as temperature changes.
8. What is the primary purpose of a control transformer?
a. Increase motor horsepower
b. Provide a suitable control voltage for control circuits
Exam Questions and Correct Answers (Verified
Answers) Plus Rationale 2027 Q&A| Instant
Download Pdf
1. What is the primary purpose of a programmable logic controller
(PLC) in an automated control system?
a. To provide mechanical support for motors
b. To store electrical energy
c. To monitor inputs, execute programmed logic, and control outputs
d. To increase the voltage supplied to equipment
Rationale: A PLC receives information from input devices such as
sensors and switches, processes that information according to its
program, and commands output devices such as relays, valves, and
motors. This makes it a central component of many industrial
automation systems.
, 2. Which device is commonly used to detect the presence or
position of a physical object without making direct contact?
a. Float switch
b. Push-button switch
c. Proximity sensor
d. Circuit breaker
Rationale: A proximity sensor detects an object within a specified
sensing range without requiring physical contact. Depending on its
design, it may detect metal, magnetic fields, capacitance, or other
characteristics.
3. In a control circuit, what is the primary function of a relay?
a. Convert AC voltage into hydraulic pressure
b. Use a control signal to switch another electrical circuit
c. Measure pipe pressure
d. Store a PLC program permanently
Rationale: A relay uses an electrically operated coil to open or close
contacts. This allows a relatively low-power control signal to operate
a separate circuit, often providing isolation between control and load
circuits.
, 4. What does the term “normally open” (NO) mean when describing
a control contact?
a. The contact is always energized
b. The contact is permanently closed
c. The contact is open when the controlling device is in its normal, de-
energized condition
d. The contact cannot be operated manually
Rationale: A normally open contact remains open in its normal state
and closes when the associated device or coil operates. NO contacts
are commonly used for start commands and signaling functions.
5. Which instrument is used to measure electrical resistance?
a. Ammeter
b. Voltmeter
c. Wattmeter
d. Ohmmeter
Rationale: An ohmmeter measures resistance in ohms. Most modern
digital multimeters combine resistance, voltage, and current
measurement functions in one instrument.
6. What is the purpose of an emergency-stop circuit?
, a. Increase motor speed during an overload
b. Automatically restart equipment after a power failure
c. Bring hazardous equipment to a safe state during an emergency
d. Increase the operating temperature of a process
Rationale: Emergency-stop functions are intended to rapidly remove
or control hazardous energy or motion when an emergency occurs.
They are safety functions and should be designed so that a fault does
not defeat the intended protective action.
7. Which type of sensor is commonly used to measure temperature
electronically?
a. Inductive proximity sensor
b. Photoelectric sensor
c. RTD
d. Limit switch
Rationale: A resistance temperature detector (RTD) measures
temperature by using the predictable change in electrical resistance of
a sensing element, commonly platinum, as temperature changes.
8. What is the primary purpose of a control transformer?
a. Increase motor horsepower
b. Provide a suitable control voltage for control circuits
