How to Freeze, Save, and Resume Simulink Simulations

Simulink allows you to capture the entire internal state of a simulation (integrator states, solver history, discrete delays, block execution memory) as a SimState object. You can save this state to disk and resume execution from that exact time point.

Method 1: Programmatic Workflow with MATLAB Code

Step 1: Run and Save the SimState (Phase 1: 0 to 10 Seconds)

Configure model parameters to export the complete operating state at the end of the run.

model = 'vdp'; % Replace with your model name
load_system(model);

% Configure model to save complete SimState
set_param(model, 'SaveCompleteSimState', 'on');
set_param(model, 'SaveFinalState', 'on');
set_param(model, 'FinalStateName', 'savedSimState');
set_param(model, 'StopTime', '10.0');
% Run Phase 1
out1 = sim(model);
% Extract and save the SimState to a .mat file
frozenState = out1.savedSimState;
save('checkpoint_t10.mat', 'frozenState');
fprintf('Simulation frozen and saved at t = 10s.\n');

Step 2: Load the Saved State and Resume (Phase 2: 10 to 25 Seconds)

Load the stored SimState object, set it as the initial state, and extend the stop time.

% Load the saved state from disk
load('checkpoint_t10.mat', 'frozenState');

% Configure model to start from the saved operating point
set_param(model, 'LoadInitialState', 'on');
set_param(model, 'InitialState', 'frozenState');
% Set new time boundaries
set_param(model, 'StartTime', '10.0');
set_param(model, 'StopTime', '25.0');
% Resume simulation
out2 = sim(model);
fprintf('Simulation resumed from t = 10s to t = 25s successfully.\n');

Method 2: GUI Configuration in Simulink

1. Open your model and press Ctrl+E to open Configuration Parameters.


2. Select Data Import/Export in the left tree.


3. To Save State:
      
   
          
   • Check Final states.
   
          
   • Set variable name (e.g. xFinal).
   
          
   • Check Save complete SimState in an operating point object.
   
      
   
   


4. To Resume State:
      
   
          
   • Check Initial state.
   
          
   • Enter the workspace variable name (e.g. xFinal).
   
          
   • Update Start time in the Solver pane to match the freeze time.
   
      
   
   

Method 3: Live Interactive Pause and Resume

Control live execution directly from the MATLAB command window or scripts:

% Pause a running simulation
set_param(model, 'SimulationCommand', 'pause');

% Resume a paused simulation
set_param(model, 'SimulationCommand', 'continue');
% Stop and terminate
set_param(model, 'SimulationCommand', 'stop');

SimState Rules and Limitations