INDUSTRIAL MAINTENANCE
TECHNICIAN TEST QUESTIONS AND
COMPLETE OPTIONS
The two basic sections of a PLC are the ✅✅ANSW-the central processing unit and the
input/output system
State the primary sections of PLCs . ✅✅ANSW-Input modules, (CPU) Central Processing Unit,
Output modules, Programming device, Operator Interface Device
PLC Input modules convert_______________ ✅✅ANSW-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"? ✅✅ANSW-Zener diode
The SCR is equivalent to what electronic device? ✅✅ANSW-thyristor
What does the PLC Central Processing unit ( CPU) do? ✅✅ANSW-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 ✅✅ANSW-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? ✅✅ANSW-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_______________
✅✅ANSW-either ON or OFF. High or Low
Pushbuttons, toggle, switches, limit switches, proximity switches, and relay contacts are all examples
of______________ ✅✅ANSW-devices that are often connected to PLC discrete inputs.
, Solenoids, relay and contactor coils, and indicator lamps are examples of______ ✅✅ANSW-
devices often connected to PLC discrete outputs.
In the on condtion, a discrete inout or output is represented internal to the PLC as_______
✅✅ANSW-a logic 1
: In the off condition, a discrete input or output is represented as_____ ✅✅ANSW-a logic 0
Analog Inputs/Outputs are____________ ✅✅ANSW-continuous, variable signals
Typical analog signals vary from ________ ✅✅ANSW-4 to 20 milliamps
Advantages of PLCs are____________ ✅✅ANSW-Smaller size, easier and faster system changes,
integrated diagnostics, immediate documentation.
The proximity switch _________ ✅✅ANSW-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 ✅✅ANSW-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? ✅✅ANSW-1/100 + 1/100 +1/100 + 1/100= 25 ohms
Identify ohms law ✅✅ANSW-V= IR
What is the purpose of the test equipment Galvanometer? ✅✅ANSW-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? ✅✅ANSW-.707% of full deflection
TECHNICIAN TEST QUESTIONS AND
COMPLETE OPTIONS
The two basic sections of a PLC are the ✅✅ANSW-the central processing unit and the
input/output system
State the primary sections of PLCs . ✅✅ANSW-Input modules, (CPU) Central Processing Unit,
Output modules, Programming device, Operator Interface Device
PLC Input modules convert_______________ ✅✅ANSW-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"? ✅✅ANSW-Zener diode
The SCR is equivalent to what electronic device? ✅✅ANSW-thyristor
What does the PLC Central Processing unit ( CPU) do? ✅✅ANSW-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 ✅✅ANSW-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? ✅✅ANSW-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_______________
✅✅ANSW-either ON or OFF. High or Low
Pushbuttons, toggle, switches, limit switches, proximity switches, and relay contacts are all examples
of______________ ✅✅ANSW-devices that are often connected to PLC discrete inputs.
, Solenoids, relay and contactor coils, and indicator lamps are examples of______ ✅✅ANSW-
devices often connected to PLC discrete outputs.
In the on condtion, a discrete inout or output is represented internal to the PLC as_______
✅✅ANSW-a logic 1
: In the off condition, a discrete input or output is represented as_____ ✅✅ANSW-a logic 0
Analog Inputs/Outputs are____________ ✅✅ANSW-continuous, variable signals
Typical analog signals vary from ________ ✅✅ANSW-4 to 20 milliamps
Advantages of PLCs are____________ ✅✅ANSW-Smaller size, easier and faster system changes,
integrated diagnostics, immediate documentation.
The proximity switch _________ ✅✅ANSW-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 ✅✅ANSW-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? ✅✅ANSW-1/100 + 1/100 +1/100 + 1/100= 25 ohms
Identify ohms law ✅✅ANSW-V= IR
What is the purpose of the test equipment Galvanometer? ✅✅ANSW-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? ✅✅ANSW-.707% of full deflection
