6.1 Identify THREE programming methods used in programmable logic controllers (PLCs). 6.2 Name TWO input devices that may be connected to the input stage of a PLC. 6.3 State THREE disadvantages of a hardwired system in comparison with a PLC system. 6.4 Explain how low-current devices, such as transistors, may be activated by the output of a PLC. 6.5 Write the simplified Boolean equation for the expression below. Use a four-variable Karnaugh map. X = A B C D + A B C D + A B C D + A B C D + A B C D 6.6 Simplify the following Boolean equation by using Boolean algebra: Q = A B C + A B + A B + A B 6.7 Refer to FIGURE 6.1. Determine the output at the following points: 6.7.1 W 6.7.2 X 6.7.3 Y 6.7.4 Z 6.8 Name the following ladder logic symbols: 6.8.1 6.8.2 6.8.3 6.9 Refer to FIGURE 6.2 and answer the questions that follow. 6.9.1 Draw the ladder logic diagram that will execute the same function in a PLC system. 6.9.2 Give ONE example where the circuit in FIGURE 6.2 may be used in an electrical application.

NSC Electrical Technology Electronics Comparator and Summing Amplifier: 6.1 Identify THREE programming m

6.1 Identify THREE programming methods used in programmable logic controllers (PLCs) - NSC Electrical Technology Electronics - Question 6 - 2016 - Paper 1

Question 6

6.1 Identify THREE programming methods used in programmable logic controllers (PLCs). 6.2 Name TWO input devices that may be connected to the input stage of a PLC. ... show full transcript

Worked Solution & Example Answer:6.1 Identify THREE programming methods used in programmable logic controllers (PLCs) - NSC Electrical Technology Electronics - Question 6 - 2016 - Paper 1

Step 1

Identify THREE programming methods used in programmable logic controllers (PLCs)

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Answer

Ladder Logic Programming
Function Block Diagram (FBD) Programming
Structured Text Programming

Step 2

Name TWO input devices that may be connected to the input stage of a PLC

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Answer

Push Buttons
Proximity Sensors

Step 3

State THREE disadvantages of a hardwired system in comparison with a PLC system

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Lack of Flexibility: Hardwired systems are challenging to modify once installed, making them less adaptable to changes in functionality.
Complexity in Maintenance: Troubleshooting and maintenance can be difficult due to the interconnected wiring.
Scalability Issues: Expanding a hardwired system often requires significant rewiring, while PLCs can be easily expanded with additional modules.

Step 4

Explain how low-current devices, such as transistors, may be activated by the output of a PLC

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Answer

Low-current devices can be activated through relays or directly via transistor outputs. In a PLC, outputs function at low voltages that can control the state of a transistor. When the PLC output is high, it energizes the transistor, allowing current to flow and activating the connected low-current device.

Step 5

Write the simplified Boolean equation for the expression below. Use a four-variable Karnaugh map

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Answer

Using a Karnaugh map to simplify the expression, we get:

$X = AB + ACD$

Step 6

Simplify the following Boolean equation by using Boolean algebra

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Answer

Starting with the equation: Q = A B C + A B + A B + A B We can factor out A B:

$Q = A B (C + 1)$ Since (C + 1) = 1, we simplify to:

$Q = A B$

Step 7

Determine the output at the following points - W

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W = A + B

Step 8

Determine the output at the following points - X

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X = A + C

Step 9

Determine the output at the following points - Y

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Answer

Y = A . B

Step 10

Determine the output at the following points - Z

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Answer

Z = (A + B)(A + C)(A . B)

Step 11

Name the following ladder logic symbols - 6.8.1

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Answer

Normally Open Contact / Switch

Step 12

Name the following ladder logic symbols - 6.8.2

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Normally Closed Contact

Step 13

Name the following ladder logic symbols - 6.8.3

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Answer

Coil

Step 14

Draw the ladder logic diagram that will execute the same function in a PLC system

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The ladder logic diagram will consist of the Start and Stop buttons controlling the coil, along with the MC1 maintaining the latch. The representation can follow typical PLC formats with clear connections.

Step 15

Give ONE example where the circuit in FIGURE 6.2 may be used in an electrical application

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Answer

This circuit can be used as a motor starter in industrial applications, enabling the control of motor operation through start and stop functions.

6.1 Identify THREE programming methods used in programmable logic controllers (PLCs) - NSC Electrical Technology Electronics - Question 6 - 2016 - Paper 1

Worked Solution & Example Answer:6.1 Identify THREE programming methods used in programmable logic controllers (PLCs) - NSC Electrical Technology Electronics - Question 6 - 2016 - Paper 1

Identify THREE programming methods used in programmable logic controllers (PLCs)

Name TWO input devices that may be connected to the input stage of a PLC

State THREE disadvantages of a hardwired system in comparison with a PLC system

Explain how low-current devices, such as transistors, may be activated by the output of a PLC

Write the simplified Boolean equation for the expression below. Use a four-variable Karnaugh map

Simplify the following Boolean equation by using Boolean algebra

Determine the output at the following points - W

Determine the output at the following points - X

Determine the output at the following points - Y

Determine the output at the following points - Z

Name the following ladder logic symbols - 6.8.1

Name the following ladder logic symbols - 6.8.2

Name the following ladder logic symbols - 6.8.3

Draw the ladder logic diagram that will execute the same function in a PLC system

Give ONE example where the circuit in FIGURE 6.2 may be used in an electrical application

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