Create, Load, Open, Save, and Close Models Programmatically

Using the functions listed on this page, you can programmatically run file operations on Simulink^® model, library, and subsystem files such as creating, loading, opening, saving, and closing a file. For example, these commands create a new model named myModel, store the model handle in the variable named h, save the model, and then close the model.

h = new_system("myModel");
save_system(h);
close_system(h);

Specify which model, library, or subsystem you want a function to act on by specifying the filename or handle as a function input argument, typically the first input argument. To reduce run time, use handles rather than filenames. For more information, see the function documentation and Get Handles and Paths. If a model, library, or subsystem is not on the MATLAB^® search path, specify the model, library, or subsystem using its file path instead of its name. Unless stated otherwise, the models, libraries, and subsystems in the examples on this page are all on the MATLAB search path.

To edit, save or close a model, library, or subsystem, it must be loaded. Changes you make to a model, library, or subsystem programmatically are not saved automatically. If you make changes without opening a model, library, or subsystem file and then open the file, the file contains your changes. However, the changes are not saved. If you close without saving, you lose the changes.

Start Simulink

You do not need to explicitly start Simulink to edit models. The software starts Simulink automatically when you run Simulink functions. However, opening a model for the first time in a MATLAB session is quicker after starting Simulink.

To start Simulink, use the start_simulink or simulink function. For example, when you start MATLAB with the -r command window option with the intention of taking action in Simulink, consider starting Simulink using the start_simulink function.

Action	Syntax
Open Simulink without opening any windows.	start_simulink
Open the Simulink start page.	simulink

Create Models, Libraries, and Subsystems

To create a new model, library, or subsystem, use the new_system function. To reuse model content or settings, use templates. Create custom templates using the Simulink.exportToTemplate function, then create new models based on the templates using the Simulink.createFromTemplate function. To create a protected model, use the Simulink.ModelReference.protect (Embedded Coder) function.

The table shows examples of these actions. The commands in the examples return the handle, h, of the new model, library, or subsystem. For more syntaxes and examples, see the function documentation.

Action	Example
Create a model in memory based on the default template.	Create a model named `myModel`. h = new_system("myModel")
Create a copy of a model in memory.	Create a model named `myModel2` based on a model named `myModel1`. h = new_system("myModel2",FromFile="myModel1");
Create a model in memory based on a subsystem in the currently loaded model.	Create a model named `myModel2` based on the subsystem named `mySubsystem` in the currently loaded model named `myModel1`. h = new_system("myModel2",Model="myModel1/mySubsystem")
Create a subsystem in memory that you can reference in multiple models.	Create a subsystem named `mySubsystem`. h = new_system("mySubsystem","Subsystem")
Create a library in memory.	Create a library named `myLibrary`. h = new_system("myLibrary","Library")
Create a model in memory based on a custom template. If the template is not on the MATLAB path, you must specify the fully-qualified path to the template file and `*.sltx` extension.	Create a model named `myModel` from the template named `myTemplate`. h = new_system("myModel",FromTemplate="myTemplate") Alternatively, use this command. h = Simulink.createFromTemplate("myTemplate",Name="myModel")
Create a protected model from an existing model.	Create a protected model from a model named `myModel` in the current folder. h = Simulink.ModelReferenceProtect("myModel") Create a protected model from a model named `myModel` in the folder located at `C:\Users\user1\Documents\myFolder`. The model is not on the MATLAB search path. h = Simulink.ModelReference.protect("myModel",... Path="C:\Users\user1\Documents\myFolder")

Load Models, Libraries, and Subsystems

Loading a model, library, or subsystem brings it into memory but does not open it in the Simulink Editor. For information about how to open a model, library, or subsystem, see the next section.

To load a model, library, or subsystem, use the load_system function. You can also load while getting a block handle using the getSimulinkBlockHandle function or while opening a file using the open_system function. The table shows examples of these actions. For more syntaxes and examples, see the function documentation.

Action	Example
Load a model, library, or subsystem into memory.	Load a model named `myModel`. The model is on the MATLAB path. h = load_system("myModel")
Load a model into memory and get the handle of a block in the model from the block path.	Load the model named `myModel` and get the handle of the block named `myBlock` in the model using a single command. h = getSimulinkBlockHandle("myModel/myBlock",true)
Load and open a model, a library, or a subsystem saved in a subsystem file.	Load and open a model named `myModel`. open_system("myModel")

To load multiple models at once using the load_system, open_system, or getSimulinkBlockHandle function, specify the models as one of the options in this table. Loading multiple models, libraries, or subsystems using the getSimulinkBlockHandle function with the models specified as filenames in a string array is not supported.

How to Specify Multiple Models, Libraries, or Subsystems	Example
Filenames specified as string array (preferred)	models = ["myModel1";"myModel2";"myModel3"]; h = load_system(models)
Filenames specified as cell array of character vectors (strings are recommended over character vectors)	models = {'myModel1';'myModel2';'myModel3'}; h = load_system(models)

Open Models, Libraries, and Subsystems

To open models, libraries, and subsystems in the Simulink Editor window, use the open_system or open function. The table shows examples of these actions. For more syntaxes and examples, see the function documentation.

Action Example

Open a model, a library, or a subsystem saved in a subsystem file.

Action	Example
Open a model, a library, or a subsystem saved in a subsystem file.	Open a model named `myModel`. open_system("myModel")
Open a subsystem in the context of the model that contains the subsystem. The model containing the subsystem must be loaded.	Suppose a model named `myModel` contains a subsystem named `mySubsystem`. The model is loaded. Open the subsystem in the context of the model. open_system("myModel/mySubsystem")
Open a referenced model in the context of a model hierarchy.	Suppose a model named `myModel1` contains a Model block named `myBlock` that references another model. Open the referenced model in the context of the `myModel1` hierarchy. path = Simulink.BlockPath("myModel1/myBlock"); open(path)

Open a model named myModel.

open_system("myModel")

Open a subsystem in the context of the model that contains the subsystem.

The model containing the subsystem must be loaded.

Suppose a model named myModel contains a subsystem named mySubsystem. The model is loaded. Open the subsystem in the context of the model.

open_system("myModel/mySubsystem")

Open a referenced model in the context of a model hierarchy.

Suppose a model named myModel1 contains a Model block named myBlock that references another model. Open the referenced model in the context of the myModel1 hierarchy.

path = Simulink.BlockPath("myModel1/myBlock");
open(path)

To open multiple models at once using the open_system function, specify the models as one of the options in this table.

How to Specify Multiple Models, Libraries, or Subsystems	Example
Filenames specified as string array (preferred)	models = ["myModel1";"myModel2";"myModel3"]; h = open_system(models)
Filenames specified as cell array of character vectors (strings are recommended over character vectors)	models = {'myModel1';'myModel2';'myModel3'}; h = open_system(models)

Save and Export Models, Libraries, and Subsystems

To save model, library, and subsystem files, use the save_system function. The table shows examples of these actions. The commands in the examples return the path of the saved model, library, or subsystem. For more syntaxes and examples, see the function documentation. For information about how to get the handle of a model, see Get Handles and Paths. To save and close models with one command, see the next section.

Note

The syntaxes in the table do not save the base workspace or model workspace. For information about how to save the model workspace, see the save_system function documentation. To save workspace variables in the base workspace, use the save function.

Action	Example
Save the current top-level model, library, or subsystem.	Open multiple models, and then save the second model you opened. To complete the task, interactively select the second model you opened to make it the current model. Then, enter this command. path = save_system
Save a new model, library, or subsystem in the current folder.	Save a new model in the current folder with the name `myModel`. path = save_system("myModel")
Save a new model, library, or subsystem in a file location other than the current folder.	On the Windows^® operating system, save a new model in the folder located at `C:\Users\user1\Documents\myFolder` with the name `myModel`. path = save_system("C:\Users\user1\Documents\myFolder\myModel") On macOS, save a new model in the folder located at `~/Documents/myFolder` with the name `myModel`. path = save_system("~/Documents/myFolder/myModel")
Save an existing model, library, or subsystem.	Save an existing model with the handle `h`. path = save_system(h)
Save existing model, library, or subsystem in a new or different file.	Save an existing model with the handle `h` to a new file named `myModel2`. path = save_system(h,"myModel2")

To export models, use the save_system with the input arguments shown in the table or use the Simulink.exportToVersion function. To export a model as a protected model, use the Simulink.ModelReference.protect (Embedded Coder) function.

Action	Example
Export to a previous MATLAB version from the past seven years.	Export a model named `myModel` with the handle `h` to the R2020a version and save the exported model with the name `myExportedModel`. path = save_system(h,"myExportedModel",ExportToVersion="R2020a") Alternatively, use this command. path = Simulink.exportToVersion("myModel","myExportedModel","R2020a")
Export to the MDL or SLX file format.	Export a model named `myModel` saved in the MDL format to the SLX file format. path = save_system("myModel.mdl","myModel.slx")
Export to the XML format.	Export a model with the handle `h` to the XML format. path = save_system(h,ExportToXML=true)
Export as a protected model (this is the same thing as creating a protected model from an existing model).	Export a model named `myModel` to the current folder as a protected model. h = Simulink.ModelReference.protect("myModel") Export a model named `myModel` in the folder located at `C:\Users\user1\Documents\myFolder` as a protected model. The model is not on the MATLAB search path. h = Simulink.ModelReference.protect("myModel",... Path="C:\Users\user1\Documents\myFolder")

To save or export multiple models, libraries, or subsystems at once using the save_system function, specify the models, libraries, or subsystems as one of the options in this table.

How to Specify Multiple Models, Libraries, or Subsystems	Example
Array of handles	models = [h1;h2;h3]; h = save_system(models)
Filenames specified as string array	models = ["myModel1";"myModel2";"myModel3"]; h = save_system(models)
Filenames specified as cell array of character vectors (strings are recommended over character vectors)	models = {'myModel1';'myModel2';'myModel3'}; h = save_system(models)

Close Models, Libraries, and Subsystems

To close models, libraries, and subsystems without saving the changes you made to them, use the bdclose function. To save and close models, libraries, and subsystems, use the close_system function. The table shows examples of these actions. For more syntaxes and examples, see the function documentation. For information about how to get the handle of a model, see Get Handles and Paths.

Action	Example
Close the current system or subsystem. Discard any unsaved changes.	Close the current top-level model without saving the changes you made. bdclose
Close the specified model, library, or subsystem. Discard any unsaved changes.	Close the model with the handle `h` without saving the changes you made. bdclose(h)
Close all open models, libraries, and subsystems. Discard any unsaved changes.	Close all open models, libraries, and subsystems without saving the changes you made. bdclose("all")
Save and then close the specified model, library, or subsystem.	Save an existing model with the handle `h` and then close the model. close_system(h,1)
Save the specified model, library, or subsystem to a new or different file and then close the model, library, or subsystem.	Save an existing model with the handle `h` to a new file named `myModel` and then close the model. close_system(h,"myModel")

To close multiple models at once using the close_system function, specify the models as one of the options in this table.

How to Specify Multiple Models, Libraries, or Subsystems	Example
Array of handles	models = [h1;h2;h3]; h = close_system(models)
Filenames specified as string array	models = ["myModel1";"myModel2";"myModel3"]; h = close_system(models)
Filenames specified as cell array of character vectors (strings are recommended over character vectors)	models = {'myModel1';'myModel2';'myModel3'}; h = close_system(models)

When you close a model with the bdclose or close_system function, the model is no longer loaded. To close a model but keep the model loaded, use this command instead, where model is the handle or name of the model.

set_param(model,Open="off")

To unload the model after running this command, you can use the bdclose or close_system function.