INDUSTRIAL MAINTENANCE 2026 TEST PAPER QUESTIONS
AND SOLUTIONS RATED A+
✔✔State the primary sections of PLCs . - ✔✔Input modules, (CPU) Central Processing
Unit, Output modules, Programming device, Operator Interface Device
✔✔PLC Input modules convert_______________ - ✔✔signals(analog or
discrete/digital) provided by various switches and sensors into logic that can be used by
the CPU
✔✔What solid state device is associated with the term "avalanche effect"? - ✔✔Zener
diode
✔✔The SCR is equivalent to what electronic device? - ✔✔thyristor
✔✔What does the PLC Central Processing unit ( CPU) do? - ✔✔evaluates the status of
inputs, outputs, and other variables as it excutes a stored program. The CPU then
sends signals to update the status of outputs.
✔✔Describe the function of Output Modules - ✔✔Output Modules convert control
signals from the CPU into digital or analog values that can be used to control various
outputs
✔✔What is the Programming Device used for? - ✔✔it is used to enter or change the
PLCs program or to monitor or change stored values. Once entered the program and
associated variables are stored in the CPU
✔✔Discrete inputs and outputs, also referred to as digital inputs and outputs
are_______________ - ✔✔either ON or OFF. High or Low
✔✔Pushbuttons, toggle, switches, limit switches, proximity switches, and relay contacts
are all examples of______________ - ✔✔devices that are often connected to PLC
discrete inputs.
✔✔Solenoids, relay and contactor coils, and indicator lamps are examples of______ -
✔✔devices often connected to PLC discrete outputs.
✔✔In the on condtion, a discrete inout or output is represented internal to the PLC
as_______ - ✔✔a logic 1
✔✔: In the off condition, a discrete input or output is represented as_____ - ✔✔a logic 0
✔✔Analog Inputs/Outputs are____________ - ✔✔continuous, variable signals
, ✔✔Typical analog signals vary from ________ - ✔✔4 to 20 milliamps
✔✔Advantages of PLCs are____________ - ✔✔Smaller size, easier and faster system
changes, integrated diagnostics, immediate documentation.
✔✔The proximity switch _________ - ✔✔senses the approach of a metallic machine
part either by a magnetic or high frequency electromagnetic field. when objects are near
by
✔✔Calculate the synchronous speed of a rotating magnetic field created by the stator
given the following information: # of poles: 4 frequency: 60Hz phases: 2 -
✔✔srpm=120xF/P 120X60/4=1800srpm
✔✔Four resistors having a value of 100 ohms each are connected in parallel. What is
the total resistance of this circuit? - ✔✔1/100 + 1/100 +1/100 + 1/100= 25 ohms
✔✔Identify ohms law - ✔✔V= IR
✔✔What is the purpose of the test equipment Galvanometer? - ✔✔Type of Ammeter
✔✔When using a multimeter to measure an output voltage, you should ensure that the
dc voltage component does not exceed what maximum voltage? - ✔✔.707% of full
deflection
✔✔What is a coulomb? - ✔✔unit of electric charge, equal to the quantity of electricity
conveyed in one second by a current of one ampere.
✔✔What is the decimal value of the highest symbol in the hexadecimal system? -
✔✔F=15 0-9A-F
✔✔What term describes the use of four binary digits to represent on decimal digit? -
✔✔BCD Binary Code Decimal
✔✔An electric motor has an apparent resistance of 15 ohms. If 8 amps of current are
flowing through the motor, what is the connected voltage? - ✔✔120v
✔✔Newly installed motor runs in reverse direction, state the suspected fault? - ✔✔leads
L1 and L3 may need to be reversed
✔✔What test equipment is used to measure KW? - ✔✔Wattmeter
✔✔What test equipment is used to measure kva - ✔✔clamp on ammeter
AND SOLUTIONS RATED A+
✔✔State the primary sections of PLCs . - ✔✔Input modules, (CPU) Central Processing
Unit, Output modules, Programming device, Operator Interface Device
✔✔PLC Input modules convert_______________ - ✔✔signals(analog or
discrete/digital) provided by various switches and sensors into logic that can be used by
the CPU
✔✔What solid state device is associated with the term "avalanche effect"? - ✔✔Zener
diode
✔✔The SCR is equivalent to what electronic device? - ✔✔thyristor
✔✔What does the PLC Central Processing unit ( CPU) do? - ✔✔evaluates the status of
inputs, outputs, and other variables as it excutes a stored program. The CPU then
sends signals to update the status of outputs.
✔✔Describe the function of Output Modules - ✔✔Output Modules convert control
signals from the CPU into digital or analog values that can be used to control various
outputs
✔✔What is the Programming Device used for? - ✔✔it is used to enter or change the
PLCs program or to monitor or change stored values. Once entered the program and
associated variables are stored in the CPU
✔✔Discrete inputs and outputs, also referred to as digital inputs and outputs
are_______________ - ✔✔either ON or OFF. High or Low
✔✔Pushbuttons, toggle, switches, limit switches, proximity switches, and relay contacts
are all examples of______________ - ✔✔devices that are often connected to PLC
discrete inputs.
✔✔Solenoids, relay and contactor coils, and indicator lamps are examples of______ -
✔✔devices often connected to PLC discrete outputs.
✔✔In the on condtion, a discrete inout or output is represented internal to the PLC
as_______ - ✔✔a logic 1
✔✔: In the off condition, a discrete input or output is represented as_____ - ✔✔a logic 0
✔✔Analog Inputs/Outputs are____________ - ✔✔continuous, variable signals
, ✔✔Typical analog signals vary from ________ - ✔✔4 to 20 milliamps
✔✔Advantages of PLCs are____________ - ✔✔Smaller size, easier and faster system
changes, integrated diagnostics, immediate documentation.
✔✔The proximity switch _________ - ✔✔senses the approach of a metallic machine
part either by a magnetic or high frequency electromagnetic field. when objects are near
by
✔✔Calculate the synchronous speed of a rotating magnetic field created by the stator
given the following information: # of poles: 4 frequency: 60Hz phases: 2 -
✔✔srpm=120xF/P 120X60/4=1800srpm
✔✔Four resistors having a value of 100 ohms each are connected in parallel. What is
the total resistance of this circuit? - ✔✔1/100 + 1/100 +1/100 + 1/100= 25 ohms
✔✔Identify ohms law - ✔✔V= IR
✔✔What is the purpose of the test equipment Galvanometer? - ✔✔Type of Ammeter
✔✔When using a multimeter to measure an output voltage, you should ensure that the
dc voltage component does not exceed what maximum voltage? - ✔✔.707% of full
deflection
✔✔What is a coulomb? - ✔✔unit of electric charge, equal to the quantity of electricity
conveyed in one second by a current of one ampere.
✔✔What is the decimal value of the highest symbol in the hexadecimal system? -
✔✔F=15 0-9A-F
✔✔What term describes the use of four binary digits to represent on decimal digit? -
✔✔BCD Binary Code Decimal
✔✔An electric motor has an apparent resistance of 15 ohms. If 8 amps of current are
flowing through the motor, what is the connected voltage? - ✔✔120v
✔✔Newly installed motor runs in reverse direction, state the suspected fault? - ✔✔leads
L1 and L3 may need to be reversed
✔✔What test equipment is used to measure KW? - ✔✔Wattmeter
✔✔What test equipment is used to measure kva - ✔✔clamp on ammeter
