About Selective Logging

You can use selective logging to log individual variables in Simscape™ blocks and combine the logs with Simulink data. You can use selective logging in addition to Simscape data logging, or you can use selective logging exclusively.

Simscape Data Logging and Selective Logging

Unlike Simscape data logging, which logs data from the entire model or block, you can use selective logging to log individual Simscape block variables and combine logs with Simulink^® signals that have logging enabled. This table shows the differences between selective logging and Simscape data logging:

Logging Method	Logged Data	Output Object	Tool to View Data
Simscape data logging	Whole model or all of the variables for selected blocks	`simscape.logging.Node`, `simscape.logging.Series`	Simscape Results Explorer or Simulation Data Inspector
Selective logging	Selected individual variables from any Simscape block in the model	`Simulink.SimulationData.Dataset`	Simulation Data Inspector

Logging and Visualizing Selected Block Variables

To specify a variable for selective logging, use the Instrumentation table in the Simscape Variables tab of the Model Data Editor. Select a Simscape block in the model and, in the Simscape Block tab, select Log Variables > Instrumentation Table. Selecting a block variable enables the block for logging and logs that block variable when you simulate the model. When the Simscape block has logging enabled, the block displays the logging badge. You can also log individual block variables in a model reference by navigating to the referenced model in the canvas and configuring the variables in the Instrumentation table. To learn more, see Log Selected Block Variables.

When you run the simulation, the variable data saves to logsout, the default Simulink.SimulationData.Dataset object workspace variable. You can also view the results in the Simulation Data Inspector.

You can manage selective logging tasks from the MATLAB command window. When you instrument your model programmatically, you can automate logging tasks to perform them across multiple models or simulations. Simscape stores the logging configuration data in your model file, where each block has a variable table and each variable configuration is defined by a VariableConfiguration object. You can configure the variable alias, the units, and whether to enable logging. After you run the simulation, you can access the recorded data from the logsout workspace variable. To learn more, see Log Selected Variables Programmatically.

Limitations

Selective logging does not support:

Rapid accelerator mode.
Component arrays.
Logging derived frequency variables.
Conditionally declared components. For composite components, this limitation includes all the externally accessible variables of conditionally declared components.