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1.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 provide
outputs.
AMEM 326 – Dr. Sotiris Omirou
2. 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
one circuit to another within the
PLC
AMEM 326 – Dr. Sotiris Omirou
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3. Unlike general purpose computers,
PLCs are
a. very expensive.
b. harder to program.
c. designed for the industrial
environment.
d. all of the above.
AMEM 326 – Dr. Sotiris Omirou
4. A programmed normally closed
PLC contact
a. with a bit status of 1 will not allow
current to flow through the contact.
b. is examined for an OFF condition.
c. is examined for an ON condition.
d. both a and b.
AMEM 326 – Dr. Sotiris Omirou
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5. Parallel connections of a ladder
logic program are typically called
a.rungs.
b.networks.
c.coils.
d.branches
AMEM 326 – Dr. Sotiris Omirou
6. The last element to be entered in a
ladder logic rung is a(n):
a.coil.
b.contact.
c.EXAMINE IF CLOSED.
d.EXAMINE IF OPEN.
AMEM 326 – Dr. Sotiris Omirou
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7. Which module of the PLC is responsible
for performing logical operations ?
a. Processor
b. Input
c. Output
d. Power supply
AMEM 326 – Dr. Sotiris Omirou
8. The status bit of switches and pushbuttons
connected to a PLC is stored in the:
a. input image table
b. output image table file
c. user program
d. all of the above
AMEM 326 – Dr. Sotiris Omirou
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9. In ladder logic programs, all outputs are
represented by:
a. contact symbols
b. coil symbols
c. schematic load devices
d. branches
AMEM 326 – Dr. Sotiris Omirou
10. The addressing format used with PLCs:
a. is always a five digit code
b. is always represented using the
octal number system
c. is standard for all manufacturers
d. none of these
AMEM 326 – Dr. Sotiris Omirou
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11. A rung consists of:
a.
b.
c.
d.
one or more inputs and only one output
a series of inputs and a series of outputs
NC or NO contacts.
pushpush-buttons or toggle switches
AMEM 326 – Dr. Sotiris Omirou
12. . Each complete horizontal line of a ladder
logic diagram is generally referred to as
a. rung
b. branch
c. input
d. output
AMEM 326 – Dr. Sotiris Omirou
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13. The abbreviations NO and NC
represent the electrical state of
switch contacts when:
power is applied
b. power is not applied
c. the switch is actuated
d. the switch is not actuated
a.
AMEM 326 – Dr. Sotiris Omirou
14. A limit switch is usually actuated by:
a. hand
b. pressure
c. contact with an object
d. an electromagnet
AMEM 326 – Dr. Sotiris Omirou
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15. Solenoid valves are available to control:
a. oil flow
b. air flow
c. water flow
d. all of these
AMEM 326 – Dr. Sotiris Omirou
16. . 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.
AMEM 326 – Dr. Sotiris Omirou
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17. The three main components of
PLCs are the input module, CPU,
and
a. actuator module
b. output module
c. operator interface
d. input device
AMEM 326 – Dr. Sotiris Omirou
18. . Prior to PLCs, many control tasks
were solved with
a. hard-wired controls
b. actuator-sensor controls
c. programmable-logic
d. computer-controllers
AMEM 326 – Dr. Sotiris Omirou
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19. . A signal which varies continuously is
called
a. digital
b. analog
c. continuous
d. variable
AMEM 326 – Dr. Sotiris Omirou
20. The binary concept makes use of the
fact that certain information
a. can exist in one of two possible states
b. can be broken down into smaller units for
easier analysis
c. can be divided into two or more categories
d. can be divided into two, or multiple of two,
categories
AMEM 326 – Dr. Sotiris Omirou
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21. In conventional logic circuits, binary 1
represents
a.
b.
c.
d.
the presence of a signal
a high voltage level
the occurrence of some event
all the above
AMEM 326 – Dr. Sotiris Omirou
22. A single rung of a ladder logic program
is arranged with
a. Input conditions connected from left to
right, with the output at the far right.
b. Input conditions connected from right to
left, with the output at the far left.
c. The output in the center and the input
conditions to the left and right of it.
d. All input conditions in parallel and all
output conditions in series.
AMEM 326 – Dr. Sotiris Omirou
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23. Which of the following is not a factor
in determining the total scan time of
PLC?
a. Memory protection.
b. Program content.
c. Program length.
d. Total number of inputs and outputs
used.
AMEM 326 – Dr. Sotiris Omirou
24. Programmed counters can:
a. count up.
b. count down.
c. be combined to count up and
down.
d. all of these.
AMEM 326 – Dr. Sotiris Omirou
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25. The PLC counter instruction is
similar to the:
a. internal relay instruction
b. transitional contact instruction
c. relay coil and contact instruction
d. timer instruction
AMEM 326 – Dr. Sotiris Omirou
26. Unlike the TON timer, the RTO
timer requires a(n):
a. timer reset instruction.
b. input condition instruction.
c. internal relay instruction.
d. instantaneous contact instruction.
AMEM 326 – Dr. Sotiris Omirou
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