Simulink vs MATLAB scripting - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a new Simulink model named 'myModel'.

Simulink

model = [1]('myModel');

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

Aopen_system

Bload_system

Cnew_system

Dsimulink

Attempts:

3 left

💡 Hint

Common Mistakes

Using open_system instead of new_system.

Using simulink which opens the Simulink start page.

The new_system function creates a new Simulink model with the specified name.

2fill in blank

medium

Complete the code to add a Gain block to the model 'myModel'.

Simulink

add_block('simulink/Commonly Used Blocks/Gain', 'myModel/Gain1', 'Position', [1]);

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

A'[30 30 60 60]'

B[30 30 60 60]

C[30, 30, 60, 60]

D'30 30 60 60'

Attempts:

3 left

💡 Hint

Common Mistakes

Putting the position vector inside quotes, making it a string.

Using commas inside the vector which is not the MATLAB syntax for vectors.

The Position parameter requires a numeric vector without quotes to specify the block's location.

3fill in blank

hard

Fix the error in the code to set the Gain value to 5.

Simulink

set_param('myModel/Gain1', 'Gain', [1]);

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

A'5'

B5.0

C'5.0'

D5

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the number without quotes causing an error.

Using double quotes which is valid but less common in MATLAB.

The Gain parameter expects a string value, so the number must be in quotes.

4fill in blank

hard

Fill both blanks to run the simulation and get the output time vector.

Simulink

simOut = [1]('myModel');
time = simOut.[2];

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

Asim

Btout

Clogsout

Dsimtime

Attempts:

3 left

💡 Hint

Common Mistakes

Using logsout which stores logged signals, not time.

Trying to access simtime which is not a valid property.

The sim function runs the model, and tout contains the simulation time vector.

5fill in blank

hard

Fill all three blanks to create a dictionary of block names and their positions for blocks with Gain > 2.

Simulink

blocks = find_system('myModel', 'BlockType', 'Gain');
positions = [1];
result = [2](block, [3](block) > 2);

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

Ablock

Bcontainers.Map

Cget_param

Dcellfun

Attempts:

3 left

💡 Hint

Common Mistakes

Using map instead of containers.Map.

Not using get_param to get block parameters.

cellfun applies a function to each block to get Gain values, containers.Map creates a dictionary, and get_param retrieves the Gain parameter.

Practice

1. What is the main difference between Simulink and MATLAB scripting?

easy

A. Simulink uses visual blocks; MATLAB scripting uses code.

B. Simulink is only for data analysis; MATLAB scripting is for graphics.

C. Simulink runs faster than MATLAB scripting always.

D. MATLAB scripting cannot create models.

Solution

1. Step 1: Understand Simulink's approach

   Simulink builds models using visual blocks and diagrams.

2. Step 2: Understand MATLAB scripting's approach

   MATLAB scripting creates and analyzes models using code commands.

3. Final Answer:

   Simulink uses visual blocks; MATLAB scripting uses code. -> Option A

4. Quick Check:

   Visual blocks vs code = D [OK]

Hint: Simulink is visual; MATLAB scripting is text-based code [OK]

Common Mistakes:

• Thinking Simulink is only for data analysis
• Believing MATLAB scripting cannot create models
• Assuming Simulink always runs faster

2. Which of the following is the correct way to open a Simulink model named myModel using MATLAB scripting?

easy

A. open('myModel.slx')

B. sim('myModel')

C. load_system('myModel')

D. run('myModel')

Solution

1. Step 1: Recall MATLAB commands for Simulink

   The command load_system('modelName') opens the Simulink model without running it.

2. Step 2: Check other options

   open() is for files but not the recommended for Simulink models; sim() runs the model; run() is for scripts.

3. Final Answer:

   load_system('myModel') -> Option C

4. Quick Check:

   Open model = load_system() [OK]

Hint: Use load_system() to open Simulink models in MATLAB [OK]

Common Mistakes:

• Using sim() to open instead of run the model
• Using open() which may not open Simulink models properly
• Confusing run() with model opening

3. Consider this MATLAB script snippet to simulate a Simulink model:

load_system('simpleModel');
simOut = sim('simpleModel', 'StopTime', '10');
result = simOut.get('yout');
disp(result);

What does result contain?

medium

A. The model file path as a string.

B. The simulation output data from the model.

C. The simulation stop time value.

D. An error because get is not a method.

Solution

1. Step 1: Understand sim() output

   The sim() function returns a Simulink.SimulationOutput object containing simulation results.

2. Step 2: Use get() method on simOut

   simOut.get('yout') retrieves logged output data named 'yout' from the simulation.

3. Final Answer:

   The simulation output data from the model. -> Option B

4. Quick Check:

   simOut.get('yout') = simulation data [OK]

Hint: sim() returns output object; get('yout') fetches data [OK]

Common Mistakes:

• Thinking get() is invalid method
• Confusing output data with file path
• Assuming result holds stop time

4. You run this MATLAB script to simulate a Simulink model:

sim('myModel')

But you get an error: Undefined function or variable 'myModel'. What is the likely cause?

medium

A. You must open the model with load_system() before simulating.

B. The sim() function is not supported for Simulink models.

C. The model name must be a full file path string.

D. The model file 'myModel.slx' is not in the current folder or path.

Solution

1. Step 1: Understand the error message

   The error means MATLAB cannot find a model named 'myModel' in the current folder or path.

2. Step 2: Check common causes

   Usually, the model file is missing or not in the MATLAB path, causing this error.

3. Final Answer:

   The model file 'myModel.slx' is not in the current folder or path. -> Option D

4. Quick Check:

   File missing = undefined variable error [OK]

Hint: Ensure model file is in current folder or MATLAB path [OK]

Common Mistakes:

• Thinking sim() cannot run models
• Believing load_system() is required before sim()
• Assuming full path is always needed

5. You want to automate running multiple Simulink models and collect their output data using MATLAB scripting. Which approach is best?

hard

A. Write a MATLAB script that loops over model names, uses sim() to run each, and stores outputs.

B. Manually open each model in Simulink and save output files.

C. Use Simulink graphical interface to drag all models into one big model.

D. Run models one by one using the Simulink GUI and copy results manually.

Solution

1. Step 1: Identify automation needs

   Automating multiple model runs requires scripting to avoid manual work.

2. Step 2: Use MATLAB scripting capabilities

   Looping over model names and running sim() collects outputs efficiently in code.

3. Step 3: Evaluate other options

   Manual or GUI methods are slow and error-prone for many models.

4. Final Answer:

   Write a MATLAB script that loops over model names, uses sim() to run each, and stores outputs. -> Option A

5. Quick Check:

   Automation with sim() loop = best practice [OK]

Hint: Use MATLAB loops with sim() to automate multiple model runs [OK]

Common Mistakes:

• Trying to automate using only Simulink GUI
• Running models manually for many cases
• Combining models graphically instead of scripting