Data Logging Options - MATLAB & Simulink (original) (raw)
When you set the Log simulation data configuration parameter toAll or Use local settings, other options in the Data Logging group box become available.
- Log simulation statistics — Select this check box if you want to access and analyze information on zero crossings during simulation. When you create a model by using the sscnew function or any of the Simscape™ model templates, this check box is selected by default. For models created using other methods, this check box is not selected by default and the zero-crossing data is not logged. For more information on using this check box, see Log Simulation Statistics.
- Record data in Simulation Data Inspector — Use this check box if you want to stream the logged simulation data to Simulation Data Inspector, to be able to view it during simulation. By default, this check box is not selected. For more information on how to configure and use the Simulation Data Inspector, see Analyze Simulation Results.
- Open viewer after simulation — Select this check box if you want to open Simscape Results Explorer, which is an interactive tool that lets you navigate and plot the simulation data logging results. By default, this check box is not selected. For more information, see Simscape Results Explorer.
If the Record data in Simulation Data Inspector check box is also selected, then the Simulation Data Inspector opens instead of the Simscape Results Explorer. - Workspace variable name — Specifies the name of the workspace variable that stores the simulation data. Subsequent simulations overwrite the data in the simulation log variable. If you want to compare data from two models or two simulation runs, use different names for the respective log variables. The default variable name is
simlog. - Decimation — Use this parameter to limit the number of data points saved, by outputting data points for every _
n_th time step, wherenis the decimation factor. The default is 1, which means that all points are logged. Specifying a different value results in the first step, and every _n_th step thereafter, being logged. For example, specifying2logs data points for every other time step, while specifying10logs data points for just one in ten steps. - Limit data points — Use this check box in conjunction with the Data history (last N steps) parameter to limit the number of data points saved. The check box is selected by default. If you clear it, the simulation log variable contains the data points for the whole simulation, at the price of slower simulation speed and heavier memory consumption.
- Data history (last N steps) — Specify the number of simulation steps to limit the number of data points output to the workspace. The simulation log variable contains the data points corresponding to the last N steps of the simulation, where N is the value that you specify for the Data history (last N steps) parameter. You have to select the Limit data points check box to make this parameter available. The default value logs simulation data for the last 10000 steps. You can specify any other positive integer number. If the simulation contains fewer steps than the number specified, the simulation log variable contains the data points for the whole simulation.
Saving data to the workspace can slow down the simulation and consume memory. To avoid this, you can use either the Decimation parameter, or Limit data points in conjunction with Data history (last N steps), or both methods, to limit the number of data points saved. The two methods work independently from each other and can be used separately or together. For example, if you specify a decimation factor of 2 and keep the default value of10000 for the Data history (last N steps) parameter, your workspace variable will contain downsampled data from the last 20,000 time steps in the simulation.
Another way to reduce memory consumption is to enable data streaming to disk, as described in Stream Logging Data to Disk.
Note
The Output options parameter, underAdditional parameters on the Data Import/Export pane of the Configuration Parameters dialog box, also affects which data points are logged.
After changing your data logging settings, rerun the simulation to generate a new data log.