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Viewing Signals in Model Reference Instances

This example shows how to use the Simulation Data Inspector to view and analyze signals in referenced models. The Simulation Data Inspector relies on signal logging so this example shows how to configure your model to log signals in referenced models.

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Configure Signals to Log in Referenced Models

The first task in setting up a referenced model to view signals using the Simulation Data Inspector is to configure that model for logging. To do that, edit the referenced model and mark the signals for logging. Four signals are already marked for logging in the referenced model. To mark the raw_output signal for logging, select the signal. Then, on the Simulation tab, select Log Signals.

Once the signals to log have been selected in the referenced model, the next step is to select which signals to actually log from the topmost model in the hierarchy. In the top model, on the Modeling tab, click Model Settings.

On the Data Import/Export pane, click the Configure Signals to Log... button to activate the Simulink Signal Logging Selector dialog.

There are two Logging modes that can be used when logging signals in referenced models. The first is Log all signals as specified in model, which will honor any logging settings that were made in referenced models. If you need to override any of those settings, such as selecting only a subset of logged signals, then you should use the Override signals mode. In this mode, you are given the ability to select a subset of loggable signals and configure their properties, such as decimation and name.

Viewing and Analyzing Logged Signals Using the Simulation Data Inspector

Once logging has been configured for a model hierarchy and all changes to the models have been saved, the model can be simulated. The simulation creates a Dataset object in the base workspace. You can analyze and view the logged data in this object using standard MATLAB® tools. In addition, Simulink® provides the Simulation Data Inspector for viewing and analyzing data created from simulations.

With the Simulation Data Inspector, you can:

  • View signal traces for any logged signals

  • Visually compare signal values for any logged signals

  • Compare signal values collected over multiple simulations

For example, you can use the Simulation Data Inspector to view the output signal of two of the instances of the model LimitedCounter. In the Simulation Data Inspector, you can see that CounterA increases more rapidly than CounterB. This behavior is expected because the Pulse Generator driving this model is running at a faster rate.

You can configure what to display in the inspect table by clicking the gear icon at the right top of the table.

Another useful tool that the Simulation Data Inspector provides is the ability to compare multiple simulation runs. This functionality can help you understand how changes to your model affect results. For example, you can change the value of the upper limit of the counter models to 8 and simulate the model again to see how that affects output values. To change the value, double click on the block MultiInstanceModelExample/upper and modify the Value parameter to 8.

Now if you compare the results from the first simulation for the output of the CounterA instance of LimitedCounter, you see that the upper limit of this signal has changed from 10 to 8, as expected. Because the tolerances are set to zero, the red octagon next to each signal indicates that the values have changed between runs.

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