8/12/2019 MSE 481 - Quiz I Solved

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SIMON FRASER UNIVERSITY

INDUSTRIAL CONTROL SYSTEMS MSE481

Summer 2014

Quiz I

Student Name:_______________________________

Student ID: ________________________________  

Page 1 of 2 

Choose the most correct answer:

1. 

PLCs were originally designed as replacements for: a) Microcomputers. b) Relay control panels. c) Analog controllers d) Digital controllers.

2.  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 control outputs based on

them.

3.  The symbol in a ladder logic diagram represents: a) Set of normally closed contacts.

b) Virtual relay coil. c) Seal-in contact. d) Field input sensing device.

4.  At the start of the PLC scan the: a) Status of all inputs are read. b) Status of all outputs are

updated. c) Program is executed. d) Diagnostics and communications tasks are executed.

5.  Programmable logic controllers are categorized according to the: a) Number of I/O points.

b) Current rating of I/O modules. c) Power rating of the I/O modules. d) Cost of the I/O modules.6.  In order for the motor to start: 

a) I/1, I/2, and I /3 must all be at logic 1.

b) I/1, I /2, and I /3 must all be at logic 0.

c) I/1 and I /2 or I /3 must be at logic 1.

d) I/1 and I /2 or I /3 will be at logic 0. 

7. 

The Boolean expression for the logic

circuit drawn in Figure 4-11 is:

a)  ( )Y A E DC B  

b) 

( )Y AE D C B  

c) 

( )Y AE D C B  

d)  ( )Y A E DCB  

8.  The output of a PLC counter is energized when the: a) Accumulated count equals the preset

count. b) Preset count is greater than the accumulated count. c) Counter input rung is true.d) Counter input rung is false.

9.  In an up-counter, when the accumulated count exceeds the preset count without a reset, theaccumulated count will: a) Set itself to zero. b) Start decrementing. c) Continue incrementing.d) Hold the accumulated value.

10. A one-shot, or transitional, contact: a) Operates the same as an NO contact instruction.b) Operates the same as an NC contact instruction. c) Operates the same as a timed closedcontact. d) Closes for only one program scan when actuated.

Figure 1

Figure 2

8/12/2019 MSE 481 - Quiz I Solved

http://slidepdf.com/reader/full/mse-481-quiz-i-solved 2/2

SIMON FRASER UNIVERSITY

INDUSTRIAL CONTROL SYSTEMS MSE481

Summer 2014

Quiz I

Student Name:_______________________________

Student ID: ________________________________  

Page 2 of 2 

11. During normal operation of the garage

parking counter in Figure 3, the

accumulated value of CTU would alwaysbe:

 

a) The same as that of CTD.b)

 150.c)

  Between 50 and 100.d)

 Between 0 and 100.

12.  In Figure 4, counter C5:1 starts counting: 

a) when the accumulated value of C5:0reaches 32,000.

b) Whenever input PB1 is actuated.c) Whenever input PB2 is actuated.d) Either b or c.

13. 

In the hardwired circuit Error! Referencesource not found., the light will stay on: a) As long as S1 is closed.b) For 5s after coil TD is energized.c) For 5s after coil TD is de-energized.d) Both a and c.

14. The timer shown in Figure 6 would be

classified as:

a) On-delay timer b) Off-delay timerc) Normally open timer d) Normally closed timer

15. For the programmed timer circuit of Figure 7,

the pilot light should come on:a) As soon as the switch is closed.b) Before the switch is closed.c) For 15 seconds after the switch is opened.d) Both a and c.

 

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7