Referenced models in Simulink

Introduction

Referenced models let you use one Simulink model inside another. This helps you build big systems by combining smaller parts.

You want to reuse a model in many projects without copying it.

You need to organize a large system into smaller, manageable pieces.

You want to test or simulate parts of a system separately.

You want to share a model with others while keeping it separate.

You want to speed up simulation by running parts independently.

Syntax

Simulink

1. Open your main Simulink model.
2. Drag a 'Model' block from the Simulink Library Browser.
3. Double-click the 'Model' block.
4. Enter the name of the referenced model file (without .slx).
5. Save and run the main model.

The referenced model file must be saved and accessible in the MATLAB path.

Changes in the referenced model automatically update in the main model.

Examples

This links the 'motor_control.slx' model inside your main model.

Simulink

Model block parameter: 'Referenced model name' = 'motor_control'

This builds a system by combining three referenced models.

Simulink

Use multiple Model blocks to include 'sensor', 'controller', and 'actuator' models.

Sample Program

This code creates a simple referenced model with a Gain block multiplying input by 5. The main model sends a constant value 2 to the referenced model and outputs the result. The output should be 10.

Simulink

% Create a simple referenced model example
% Step 1: Create a referenced model 'simple_gain.slx' with a Gain block
% Step 2: Create a main model 'main_model.slx' and add a Model block referencing 'simple_gain'

% For demonstration, simulate the referenced model programmatically

% Create referenced model
new_system('simple_gain')
add_block('simulink/Commonly Used Blocks/Gain','simple_gain/Gain')
set_param('simple_gain/Gain','Gain','5')
save_system('simple_gain')
close_system('simple_gain')

% Create main model
new_system('main_model')
add_block('simulink/Commonly Used Blocks/Model','main_model/ReferencedModel')
set_param('main_model/ReferencedModel','ModelName','simple_gain')
add_block('simulink/Commonly Used Blocks/Constant','main_model/Constant')
set_param('main_model/Constant','Value','2')
add_block('simulink/Commonly Used Blocks/Out1','main_model/Out1')

% Connect blocks
add_line('main_model','Constant/1','ReferencedModel/1')
add_line('main_model','ReferencedModel/1','Out1/1')

save_system('main_model')

% Simulate main model
simOut = sim('main_model');

% Get output
output = simOut.get('yout');

% Display output
fprintf('Output of referenced model simulation: %g\n', output.signals.values(end));

Important Notes

Referenced models help keep your projects clean and organized.

Make sure referenced models are saved before running the main model.

You can update referenced models independently without changing the main model.

Summary

Referenced models let you reuse and organize Simulink models easily.

They help build complex systems from smaller parts.

Changes in referenced models update automatically in the main model.

Practice

1. What is the main purpose of using Referenced models in Simulink?

easy

A. To reuse parts of models and simplify large projects

B. To create new Simulink blocks from scratch

C. To export models as images

D. To run simulations faster by skipping blocks

Solution

1. Step 1: Understand the role of referenced models

   Referenced models allow you to include one model inside another, making reuse possible.

2. Step 2: Connect reuse to project management

   By reusing parts, you keep big projects organized and easier to update.

3. Final Answer:

   To reuse parts of models and simplify large projects -> Option A

4. Quick Check:

   Referenced models = reuse and simplify [OK]

Hint: Think reuse and organization for big Simulink projects [OK]

Common Mistakes:

• Confusing referenced models with creating new blocks
• Thinking referenced models speed up simulation by skipping
• Assuming referenced models export images

2. Which of the following is the correct way to add a referenced model in Simulink?

easy

A. Drag a Model block and set its Model name parameter to the referenced model file

B. Use the MATLAB command add_block('model') without parameters

C. Copy and paste the entire model into the current model

D. Create a new subsystem and name it after the referenced model

Solution

1. Step 1: Recall how to include referenced models

   Simulink uses Model blocks to include referenced models by specifying the model file name.

2. Step 2: Check options for correctness

   Drag a Model block and set its Model name parameter to the referenced model file correctly describes dragging a Model block and setting its Model name parameter.

3. Final Answer:

   Drag a Model block and set its Model name parameter to the referenced model file -> Option A

4. Quick Check:

   Model block + Model name = referenced model [OK]

Hint: Use Model block and set model name to reference [OK]

Common Mistakes:

• Using add_block without parameters causes errors
• Copy-pasting duplicates instead of referencing
• Naming subsystems does not create references

3. Given a Simulink model with a Model block referencing subsystemA, what happens if subsystemA is updated externally and saved before simulation?

medium

A. Simulation fails with an error about missing blocks

B. The main model ignores changes and uses the old version

C. The main model uses the updated subsystemA during simulation

D. The referenced model is duplicated inside the main model automatically

Solution

1. Step 1: Understand referenced model behavior on update

   Referenced models reflect changes made externally when saved before simulation.

2. Step 2: Analyze simulation effect

   The main model uses the latest saved version of the referenced model during simulation.

3. Final Answer:

   The main model uses the updated subsystemA during simulation -> Option C

4. Quick Check:

   Referenced models update = main model uses latest [OK]

Hint: Referenced models always use saved latest version at simulation [OK]

Common Mistakes:

• Assuming main model caches old referenced model version
• Thinking simulation fails if referenced model changes
• Believing referenced models duplicate automatically

4. You added a referenced model block but get an error: Model file not found. What is the most likely cause?

medium

A. The simulation time is set to zero

B. The referenced model file path is incorrect or missing

C. The referenced model has no input ports

D. The main model is not saved

Solution

1. Step 1: Identify cause of 'Model file not found'

   This error usually means Simulink cannot locate the referenced model file due to wrong or missing path.

2. Step 2: Check other options for relevance

   Saving main model, input ports, or simulation time do not cause this error.

3. Final Answer:

   The referenced model file path is incorrect or missing -> Option B

4. Quick Check:

   File not found = wrong or missing path [OK]

Hint: Check referenced model file path if 'not found' error appears [OK]

Common Mistakes:

• Ignoring file path issues
• Blaming simulation time or ports incorrectly
• Not saving main model but error is unrelated

5. You want to create a large Simulink project with multiple teams working on different parts. How do referenced models help in this scenario?

hard

A. Referenced models run simulations independently without integration

B. Referenced models automatically merge all team changes into one file

C. Referenced models prevent any changes once included in the main model

D. Each team works on separate referenced models that are included in the main model, easing collaboration

Solution

1. Step 1: Understand team collaboration with referenced models

   Referenced models allow teams to work on separate model files independently.

2. Step 2: Connect referenced models to main model integration

   The main model includes these referenced models, making integration easier and organized.

3. Final Answer:

   Each team works on separate referenced models that are included in the main model, easing collaboration -> Option D

4. Quick Check:

   Referenced models = team collaboration and modular design [OK]

Hint: Use referenced models for modular teamwork in big projects [OK]

Common Mistakes:

• Thinking referenced models merge files automatically
• Assuming referenced models lock changes
• Believing referenced models simulate independently without integration