Source blocks (Constant, Step, Sine Wave, Ramp) in Simulink - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a Constant block with value 5.

Simulink

constant_block = Simulink.BlockDiagram.createBlock('simulink/Sources/Constant', 'Value', [1])

Drag options to blanks, or click blank then click option'

A10

B-5

C0

D5

Attempts:

3 left

💡 Hint

Common Mistakes

Using a value other than 5.

Leaving the value empty.

The Constant block outputs a fixed value. Here, the value should be 5.

2fill in blank

medium

Complete the code to create a Step block with step time at 2 seconds.

Simulink

step_block = Simulink.BlockDiagram.createBlock('simulink/Sources/Step', 'StepTime', [1])

Drag options to blanks, or click blank then click option'

A2

B5

C1

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Setting step time to 0 or 1 instead of 2.

Confusing step time with initial value.

The Step block changes its output at the specified step time. Here, it should step at 2 seconds.

3fill in blank

hard

Fix the error in the code to create a Sine Wave block with amplitude 3.

Simulink

sine_block = Simulink.BlockDiagram.createBlock('simulink/Sources/Sine Wave', 'Amplitude', [1])

Drag options to blanks, or click blank then click option'

A1

B0

C3

D-3

Attempts:

3 left

💡 Hint

Common Mistakes

Using amplitude 1 or 0 which changes the wave height.

Using negative amplitude which flips the wave.

The Sine Wave block outputs a sine wave with the specified amplitude. Here, it should be 3.

4fill in blank

hard

Fill both blanks to create a Ramp block with slope 4 and initial output 1.

Simulink

ramp_block = Simulink.BlockDiagram.createBlock('simulink/Sources/Ramp', 'Slope', [1], 'InitialOutput', [2])

Drag options to blanks, or click blank then click option'

A4

B1

C0

D5

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing slope and initial output values.

Using zero slope which produces a constant output.

The Ramp block outputs a signal that increases linearly. Slope controls the rate, InitialOutput is the start value.

5fill in blank

hard

Fill all three blanks to create a Step block with step time 3, initial value 0, and final value 10.

Simulink

step_block = Simulink.BlockDiagram.createBlock('simulink/Sources/Step', 'StepTime', [1], 'InitialValue', [2], 'FinalValue', [3])

Drag options to blanks, or click blank then click option'

A0

B10

C3

D5

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping initial and final values.

Setting wrong step time.

The Step block changes output from InitialValue to FinalValue at StepTime. Here, step time is 3, initial value 0, final value 10.

Practice

1. Which Simulink source block provides a fixed value throughout the simulation?

easy

A. Ramp block

B. Step block

C. Sine Wave block

D. Constant block

Solution

1. Step 1: Understand the behavior of each source block

   The Constant block outputs a fixed value that does not change over time. The Step block changes value at a specified time. The Sine Wave block outputs a sinusoidal signal. The Ramp block outputs a linearly increasing or decreasing signal.

2. Step 2: Identify the block with fixed output

   Only the Constant block maintains the same value throughout the simulation without change.

3. Final Answer:

   Constant block -> Option D

4. Quick Check:

   Fixed value = Constant block [OK]

Hint: Constant means no change over time [OK]

Common Mistakes:

• Confusing Step block with Constant because both output numbers
• Thinking Sine Wave can be constant
• Assuming Ramp outputs fixed value

2. Which of the following is the correct way to set a Step block to change value at time 5 seconds?

easy

A. Set Final value to 0 and Step time to 5

B. Set Step time to 0 and Initial value to 5

C. Set Step time to 5 and Final value to new value

D. Set Initial value to 5 and Step time to 10

Solution

1. Step 1: Recall Step block parameters

   The Step block changes its output from Initial value to Final value at the specified Step time.

2. Step 2: Identify correct parameter settings for change at 5 seconds

   To change at 5 seconds, Step time must be 5. Final value is the new output after 5 seconds.

3. Final Answer:

   Set Step time to 5 and Final value to new value -> Option C

4. Quick Check:

   Step time = 5 for change at 5 seconds [OK]

Hint: Step time sets when value changes [OK]

Common Mistakes:

• Setting Step time to 0 causes immediate change
• Confusing Initial and Final values
• Setting wrong Step time for desired change

3. What output values will a Ramp block produce at times t = 0, 2, and 4 seconds if its slope is set to 3 and initial output is 1?

medium

A. [1, 4, 7]

B. [1, 7, 13]

C. [0, 6, 12]

D. [1, 3, 5]

Solution

1. Step 1: Understand Ramp block output formula

   Output = Initial output + slope * time. Here, initial output = 1, slope = 3.

2. Step 2: Calculate output at each time

   At t=0: 1 + 3*0 = 1; t=2: 1 + 3*2 = 7; t=4: 1 + 3*4 = 13.

3. Step 3: Match calculated values with options

   The calculated outputs [1, 7, 13] match [1, 7, 13].

4. Final Answer:

   [1, 7, 13] -> Option B

5. Quick Check:

   Output = 1 + 3*t matches [1,7,13] [OK]

Hint: Ramp output = initial + slope x time [OK]

Common Mistakes:

• Forgetting to add initial output
• Multiplying slope by wrong time values
• Mixing up options with similar numbers

4. A user sets a Step block with Initial value = 0, Final value = 10, but the output never changes during simulation. What is the likely error?

medium

A. Step time is set after simulation end time

B. Initial value equals Final value

C. Step time is set to 0

D. Final value is less than Initial value

Solution

1. Step 1: Understand Step block timing

   The Step block changes output at Step time. If Step time is after simulation ends, change never happens during simulation.

2. Step 2: Analyze given values

   Initial value = 0, Final value = 10, so values differ. If output never changes, likely Step time is beyond simulation time.

3. Final Answer:

   Step time is set after simulation end time -> Option A

4. Quick Check:

   Step time > simulation time means no output change [OK]

Hint: Step time must be within simulation time [OK]

Common Mistakes:

• Assuming Initial equals Final value causes no change
• Ignoring simulation stop time
• Confusing Step time with Final value

5. You want to simulate a signal that starts at 2, stays constant until 3 seconds, then increases smoothly by 4 units every second. Which combination of source blocks should you use?

hard

A. Step block from 2 to 2 at 3 seconds and Ramp block starting at 3 seconds with slope 4

B. Step block changing from 2 to 6 at 3 seconds

C. Sine Wave block with amplitude 2 and frequency 4

D. Constant block with value 2 and Ramp block starting at 3 seconds with slope 4

Solution

1. Step 1: Analyze signal requirements

   Signal starts at 2, constant until 3 seconds, then increases smoothly by 4 units per second.

2. Step 2: Choose blocks to model behavior

   Use Step block to hold value at 2 until 3 seconds (change from 2 to 2 at 3 seconds means no jump). Then use Ramp block starting at 3 seconds with slope 4 to increase smoothly.

3. Step 3: Confirm other options

   Constant block with value 2 and Ramp block starting at 3 seconds with slope 4 is incorrect because Ramp cannot start at 3 seconds alone without Step block. Step block changing from 2 to 6 at 3 seconds is wrong because Step block changes instantly, not smoothly. Sine Wave block with amplitude 2 and frequency 4 is unrelated sine wave.

4. Final Answer:

   Step block from 2 to 2 at 3 seconds and Ramp block starting at 3 seconds with slope 4 -> Option A

5. Quick Check:

   Step holds constant, Ramp adds smooth increase [OK]

Hint: Combine Step for hold and Ramp for smooth increase [OK]

Common Mistakes:

• Using only Step block causes sudden jump
• Using Constant block alone can't model increase
• Confusing Sine Wave with linear increase