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Final Exam
Name:
ID
:
Notes
1. This is a closed book & closed notes exam
2. There are ( 6 ) problems
3. Do ALL the problems
4. The time allowed is ( 100 ) minuets
5. The exam weights 40% of the nal grade
Results:
Problem Marks
I
II
III
IV
V
VI
Total
/
/
/
/
/
/
12
08
15
05
15
15
/ 70
1
Scratch space...
2
I (3 points each)
Explain in details the course project you were wroking on:
1. The process and the sequence of operation
2. The input and output devices and types that are used in the project
3. The PLC program for implementation
4. How could you have improved the project
3
II (2 points each)
Answer the questions, in sequence, for the jump-to- label program in Figure 1. Assume all switches are turned
o after each operation.
a. Switch S3 is turned on. Will output PL1 be ener- gized? Why?
b. Switch S2 is turned on i rst, then switch S5 is turned on. Will output PL4 be energized? Why?
c. Switch S3 is turned on and output PL1 is ener- gized. Next, switch S2 is turned on. Will output PL1 be
energized or de-energized after turning on switch S2? Why?
d. All switches are turned on in order according to the following sequence: S1, S2, S3, S5, S4. Which pilot
lights will turn on?
4
III (part 1:10 points, part 2: 5 points)
1. Write a program that will increment a counter's accumulated value 1 count every 60 seconds. A second
counter's accumulated value will increment 1 count every time the rst counter's value reaches 60. The rst
counter will reset when its accumulated value reaches 60, the second counter will reset when its accumulated
value reaches 12.
2. Write a program that uses the mask move instruction to move only the upper 8 bits of the value stored at
address I:2.0 to address O:2.1 and to ignore the lower 8 bits.
5
IV (1 point each)
Answer each of the following with reference to the overi ll alarm program shown in Figure 2 .
a. Assume that the vessel is lling and has reached the 300-lb point. State the status of each of the logic rungs
(true or false) at this point.
b. Assume that the vessel is lling and has reached the 480-lb point. State the value of the number stored in
each of the following words at this point: (1) I:012 (2) N7:1
c. Assume that the vessel is lled to a weight of 502 lb. State the status of each of the logic rungs (true or false)
for this condition
d. Assume that the vessel is lled to a weight of 510 lb. State the value of the number stored in each of the
following words for this condition: (1) I:012 (2) N7:1
e. With the vessel lled to a weight of 510 lb, state the status of each of the logic rungs (true or false).
6
V (A: 3 points, B: 6 points, C: 6 points)
Figure 3, shows a drilling process that needs to be controlled using PLC, the sequence of operation is as follows:
1. In the beginning of the drilling cycle the Upper Limit Switch is closed
2. The START button starts the drilling cycle (push button)
3. The drill motor M1 must start. At the same time, the vertical motor M2 must start to descend the drill
4. The drill will stop at the Lower Limit Switch. At this time, the vertical motor start to ascend the drill .
5. The drill motor must stop just at the upper position. Wait for a new drilling cycle
6. Stop button is optional (push button)
A. Point out all input and output devices for this process
B. Make a ladder logic PLC program for the implementation of the process
C. Draw the timing diagram of the process (for each input and output you need to draw a line)
7
VI (part 1: 3 points, part 2: 12 points (each program 6 points))
1. List the names of PLC programming languages
2. Rewrite the following ladder diagram with any other two PLC programming language of your choice (A
motor on/o, with signal lamps, ladder diagram.) you can change the addresses if you like, just indicate the ones
that you will be using.
8