Diagnostics

View diagnostics for models, configure and customize diagnostic checks, understand diagnostic viewer layout

Simulink® provides diagnostic messages when certain conditions are detected during a Simulink operation on a model. The diagnostic messages are captured under error, information, or warning categories.

The diagnostic messages you encounter in programmatic operations are displayed in the MATLAB® Command Window, while those you encounter during a Simulink user interface operation are displayed in the Diagnostic Viewer. For example, if you simulate a model from the MATLAB command prompt using the sim function, the diagnostics messages are displayed in the Command Window. However, if you run a simulation from the Simulink Toolstrip, the diagnostic messages are displayed in the Diagnostic Viewer.

You can customize the diagnostic messages, and also customize the conditions the software checks to either produce errors or warnings.

The diagnostics for model are displayed in the Diagnostic Viewer user interface. To know more about the Diagnostic Viewer, see Diagnostic Viewer.

You can also add Model Verification blocks to your model, to check the condition of specific signals. For more information about Model Verification, see topics listed under Run Model Advisor Checks.

Functions

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sldiagviewer.createStageCreate stage to display diagnostic messages
sldiagviewer.reportErrorReport error messages in Diagnostic Viewer
sldiagviewer.reportInfoReport information messages in Diagnostic Viewer
sldiagviewer.reportWarningReport warning messages in Diagnostic Viewer
sldiagviewer.diaryLog diagnostic messages and build information in file
sldiagviewer.reportSimulationMetadataDiagnosticsDisplay errors and warnings in Simulink.SimulationOutput object using Diagnostic Viewer (Since R2020b)
sldiagviewer.Comparator.compareCompare diagnostic details between model operations (Since R2025a)
sldiagviewer.Comparator.displayResultDisplay differences in diagnostic details of model operations (Since R2025a)
sldiagviewer.Comparator.compareWithBaselineCompare diagnostic details with saved baseline (Since R2025a)
sldiagviewer.Comparator.convertToJsonConvert diagnostic details comparison to JSON format (Since R2025a)
Simulink.restoreDiagnosticRestore diagnostic warnings to a specific block, subsystem, or model
Simulink.suppressDiagnosticSuppress a diagnostic from a specific block
Simulink.getSuppressedDiagnostics Return Simulink.SuppressedDiagnostic objects associated with a block, subsystem, or model
modeladvisorOpen Model Advisor
sldiagnosticsDisplay diagnostic information of Simulink system
Simulink.BlockDiagram.getChecksumReturn model checksum
Simulink.SubSystem.getChecksumReturn checksum of nonvirtual subsystem

Classes

Simulink.SuppressedDiagnosticSuppress diagnostic messages from specific block
sldiagviewer.DiagnosticReceiverCreate receiver to get diagnostic details of model operation (Since R2025a)

Namespaces

sldiagviewerSummary of classes, functions, and namespaces associated with diagnostics
sldiagviewer.ComparatorSummary of functions for comparing diagnostics (Since R2025a)

Apps

Parameter Quantization AdvisorInspect numerical issues related to parameter quantization (Since R2022b)

Tools

Diagnostic ViewerView, compare, and diagnose errors and warnings generated by Simulink models

Model Settings

Model Configuration Parameters: Diagnostics
Model Configuration Parameters: Sample Time Diagnostics
Model Configuration Parameters: Data Validity
Model Configuration Parameters: Type Conversion Diagnostics
Model Configuration Parameters: Connectivity Diagnostics
Model Configuration Parameters: Compatibility Diagnostics
Model Configuration Parameters: Model Referencing Diagnostics
Model Configuration Parameters: Stateflow Diagnostics

Checks

Runtime diagnostics for S-functions
Check if read/write diagnostics are enabled for data store blocks
Check for non-continuous signals driving derivative ports
Check for Discrete-Time Integrator blocks with initial condition uncertainty
Check for potentially delayed function-call subsystem return values

Topics

Diagnostic Viewer

Related Information