Name: ________________________ Class: ___________________ Date: __________
ID: A
PRE_POST Test - PLC Intermediate
True/False
Indicate whether the sentence or statement is true or false.
____
1. The number of PLC timers used in a program can be increased or decreased without wiring changes.
____
2. Even though each manufacturer may represent timers differently on the ladder diagram, all timers operate the
same.
____
3. A PLC down-counter decrements whenever the count input transfers from an "off" state to an "on" state.
____
4. With Microsoft's Windows you can use multiple specialized applications that run concurrently and work
together.
____
5. The system controller for a numerical control system is usually an industrial computer.
Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
____
____
6. In general, the three different types of PLC timers are
a. TON, TOF, and RTO
c. TON, ACC, and RTO
b. TON, TOF, and PRE
d. TT, EN, and DN
7. The timing diagram shown is that of an
a. on-delay timer circuit (NOTC contact)
b. on-delay timer circuit (NCTO contact)
c. off-delay timer circuit (NOTO contact)
d. off-delay timer circuit (NCTC contact)
____ 8. The timer instruction is
a. an input instruction
c. either a or b
b. an output instruction
d. both a or b
____ 9. The ____ bit operates the same as an instantaneous contact on a timer relay.
a. enable
c. timer-timing
b. done
d. timer number
____ 10. Which of the following statements is not true for a retentive on-delay timer?
a. The timer accumulates time when it is energized.
b. The timer does not reset to zero when it is de-energized.
c. The timer requires a reset instruction to reset the accumulated value of the timer to zero.
d. The reset input to the timer will not override the control input.
1
Name: ________________________
ID: A
____ 11. When the timing of a device is not reset due to a loss of power, the timer is said to be:
a. at fault
c. continuous
b. retentive
d. secured
____ 12. The ____ value of a PLC counter is the current count based on the number of times the rung goes from
false-to-true.
a. preset
c. accumulated
b. overflow
d. underflow
____ 13. When the counter reset instruction is true it resets the
a. accumulated value
c. counter enable bit
b. counter done bit
d. all of these
____ 14. When the accumulated count is equal to or greater than the preset count, which bit will be true?
a. OV
c. CU
b. DN
d. CD
____ 15. The incremental encoder creates
a. a pure dc waveform
c. a sawtooth waveform
b. an ac sine waveform
d. a series of square waves
____ 16. The maximum speed of transitions you can count is determine by
a. the amount of PLC memory
c. the preset value of the counter
b. your program's scan time
d. all of these
____ 17. When the MCR in the start fence is false
a. all rungs within the zone are treated as false
b. the scan ignores all of the inputs within the zone
c. all non-retentive outputs within the zone are de-energized
d. all of these
____ 18. The force instructions
a. will force bits on only
b. will force bits off only
c. if used indiscriminately, could cause haphazard machine operation
d. can only be used to force outputs
____ 19. A selectable timed interrupt (STI) function allows you to
a. freeze outputs in their last state
b. latch outputs when de-energized
c. interrupt the scan of the main program on a time basis
d. interrupt the scan of the main program on an event basis
____ 20. For the rung shown, when input A is ____ the number stored at N7:53 will be ____.
a.
b.
true, -300
false, -300
c.
d.
2
true, +300
false, +300
Name: ________________________
ID: A
____ 21. Technician A says computer disk drives are used for placing information into the computer as well as storing
information from the computer. Technician B says the hard disk mass storage is located permanently within the
computer. Who is correct?
a. Technician A only
b. Technician B only
c. both Technician A and Technician B
d. neither Technician nor Technician B
____ 22. The main difference between the PLC and the cell controller is the ____ used.
a. type of I/O
c. type of memory
b. type of processor
d. programming language
____ 23. Technician A says in a bus network all transmissions must be sent to a hub which then sends them to the
correct node. Technician B says in a star network communications can take place between any two nodes
without information having to be routed through a central node. Who is correct?
a. Technician A only
b. Technician B only
c. both Technician A and Technician B
d. neither Technician nor Technician B
____ 24. Technician A says point-to-point programming involves straight-line movements. Technician B says
point-to-point programming requires the ability to control motions on two or more machine axes
simultaneously. Who is correct?
a. Technician A only
b. Technician B only
c. both Technician A and Technician B
d. neither Technician nor Technician B
____ 25. Technician A says all robots use hydraulic servo-drives. Technician B says the shape of the robot work
envelope is determined by the type of robotic controller used. Who is correct?
a. Technician A only
b. Technician B only
c. both Technician A and Technician B
d. neither Technician nor Technician B
Completion
Complete each sentence or statement.
26. The ____________________ instruction is used to identify the ladder rung that is the target destination of the
jump instruction.
27. Standard arithmetic instructions include: ____________________, ____________________,
____________________,and ____________________.
28. Personal computers (PCs) with ____________________ cards that plug directly into their expansion slots can
be used for machine control.
29. PC power supplies are rated in terms of ____________________ they can safely supply.
30. For an Allen-Bradley SLC-500, the result of the math instruction is stored at the ____________________
address.
3
ID: A
PRE_POST Test - PLC Intermediate
Answer Section
TRUE/FALSE
1.
2.
3.
4.
5.
ANS:
ANS:
ANS:
ANS:
ANS:
T
T
T
T
T
MULTIPLE CHOICE
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
A
B
B
A
D
B
C
D
B
D
B
D
C
C
A
C
D
D
A
D
COMPLETION
26.
27.
28.
29.
30.
ANS:
ANS:
ANS:
ANS:
ANS:
label
addition, subtraction, multiplication, division
I/O
watts
destination
1