Simulink interface overview in MATLAB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to open a Simulink model named 'myModel'.

MATLAB

open_system('[1]');

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

A'simulink'

BmyModel

C'myModel'

Dmodel

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to put the model name in quotes.

Using the model name without quotes causing an error.

To open a Simulink model, you must provide the model name as a string, including quotes.

2fill in blank

medium

Complete the code to simulate a Simulink model named 'myModel'.

MATLAB

sim('[1]');

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

A'myModel'

BmyModel

C'simulink'

Dmodel

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the model name without quotes.

Using incorrect function names.

The 'sim' function requires the model name as a string, so it must be enclosed in quotes.

3fill in blank

hard

Fix the error in the code to load a Simulink library named 'simulink'.

MATLAB

load_system('[1]');

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

A'simulink'

Bsimulink

CSimulink

D'Simulink'

Attempts:

3 left

💡 Hint

Common Mistakes

Not using quotes around the library name.

Using incorrect capitalization.

The 'load_system' function requires the library name as a string with quotes.

4fill in blank

hard

Fill both blanks to create a new Simulink model named 'newModel' and open it.

MATLAB

new_system([1]);
open_system([2]);

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

A'newModel'

BnewModel

C'myModel'

DmyModel

Attempts:

3 left

💡 Hint

Common Mistakes

Using variable names without quotes.

Using different names in the two functions.

Both functions require the model name as a string with quotes.

5fill in blank

hard

Fill all three blanks to set the stop time to 10, simulate the model 'testModel', and close it.

MATLAB

set_param('[1]', 'StopTime', '[2]');
sim('[3]');
close_system('[1]');

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

AtestModel

B10

CmyModel

D20

Attempts:

3 left

💡 Hint

Common Mistakes

Using numbers without quotes for stop time.

Using different model names in the functions.

Use the model name 'testModel' as a string for set_param, sim, and close_system. The stop time must be a string representing the number '10'.

Practice

1. What is the primary purpose of the Simulink interface in MATLAB?

easy

A. To write low-level assembly code

B. To build system models visually using blocks

C. To create 3D animations

D. To perform statistical data analysis

Solution

1. Step 1: Understand Simulink's role

   Simulink is designed for visual modeling of systems using blocks.

2. Step 2: Compare options

   Options B, C, and D describe unrelated tasks to Simulink's main function.

3. Final Answer:

   To build system models visually using blocks -> Option B

4. Quick Check:

   Simulink = Visual block modeling [OK]

Hint: Simulink is about visual block diagrams, not coding [OK]

Common Mistakes:

• Confusing Simulink with MATLAB scripting
• Thinking Simulink is for data analysis
• Assuming Simulink creates animations

2. Which MATLAB command is used to open a Simulink model named myModel?

easy

A. open('myModel.slx')

B. sim('myModel')

C. load('myModel')

D. run('myModel')

Solution

1. Step 1: Identify command to open model

   The open command with the model filename opens the Simulink model.

2. Step 2: Differentiate other commands

   sim runs the model, load loads variables, run executes scripts.

3. Final Answer:

   open('myModel.slx') -> Option A

4. Quick Check:

   Open model = open('filename') [OK]

Hint: Use open('model.slx') to open Simulink models [OK]

Common Mistakes:

• Using sim() to open instead of run the model
• Confusing load() with open()
• Trying run() which is for scripts

3. What will be the output of the following MATLAB commands?

open_system('vdp');
sim('vdp');
logsout.getElement(1).Values.Data(end)

Assuming vdp is a valid Simulink model and simulation runs successfully.

medium

A. The total simulation time

B. An error because open_system does not run the model

C. The last data value from the first logged signal of the simulation

D. The initial value of the simulation signal

Solution

1. Step 1: Understand commands

   open_system('vdp') opens the model, sim('vdp') runs it, and logsout.getElement(1).Values.Data(end) accesses the last data point of the first logged signal.

2. Step 2: Interpret output

   The command returns the final value of the first signal logged during simulation.

3. Final Answer:

   The last data value from the first logged signal of the simulation -> Option C

4. Quick Check:

   sim() runs model, logsout returns data [OK]

Hint: sim() runs model; logsout stores signals [OK]

Common Mistakes:

• Thinking open_system runs the model
• Confusing signal data with simulation time
• Accessing initial instead of last data point

4. You try to run sim('myModel') but get an error: Undefined function or variable 'myModel'. What is the most likely cause?

medium

A. The model file myModel.slx is not in the current folder or MATLAB path

B. You forgot to open the model first with open_system

C. The sim command only works with built-in models

D. The model name must be in uppercase letters

Solution

1. Step 1: Analyze error message

   The error indicates MATLAB cannot find the model file named 'myModel'.

2. Step 2: Identify cause

   This usually happens if the model file is not in the current folder or MATLAB path.

3. Final Answer:

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

4. Quick Check:

   File location missing causes undefined variable error [OK]

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

Common Mistakes:

• Assuming open_system must be called before sim
• Thinking sim only works on built-in models
• Believing model names must be uppercase

5. You want to programmatically change the value of a block parameter named Gain in a Simulink model controlSys before running the simulation. Which sequence of commands correctly does this?

hard

A. load_system('controlSys'); set_param('controlSys', 'Gain', '5'); sim('controlSys');

B. open_system('controlSys'); set_param('Gain', 'Gain', 5); sim('controlSys');

C. sim('controlSys', 'Gain', 5);

D. set_param('controlSys/Gain', 'Gain', '5'); sim('controlSys');

Solution

1. Step 1: Identify correct set_param usage

   The set_param function requires the full block path and parameter name as strings. 'controlSys/Gain' is the block path, 'Gain' is the parameter, and '5' is the new value as a string.

2. Step 2: Confirm simulation command

   After setting the parameter, sim('controlSys') runs the model with updated parameters.

3. Final Answer:

   set_param('controlSys/Gain', 'Gain', '5'); sim('controlSys'); -> Option D

4. Quick Check:

   set_param with full path + sim() runs updated model [OK]

Hint: Use set_param('model/block', 'param', 'value') before sim() [OK]

Common Mistakes:

• Using set_param without full block path
• Passing numeric value instead of string for parameter
• Trying to pass parameters directly in sim()