Main Content

Interface Specification Using Bus Objects

Open Model

This example shows how to propagate buses into referenced models. It also shows how you can simulate the referenced models independently using logged signal data from the parent model.

Open the Example Model

Open and simulate the example model sldemo_mdlref_bus.

Examine the Model

The model contains a Model block named CounterA that references sldemo_mdlref_counter_bus, which is a model of a simple counter.

An array of buses named COUNTERBUS feeds the data and the saturation limits of the counter into the model. The buses named COUNTERBUS each contain two elements: a data signal and a nested bus named LIMITBUS. The data is used in counting, and LIMITBUS contains the upper and lower limit values of the counter.

The Model block has a second input port that connects to a bus named INCREMENTBUS. This bus contains elements that change the increment and reset the counter.

The model uses a data dictionary file named sldemo_mdlref_bus.sldd that contains Simulink.Bus objects that define the elements of COUNTERBUS, LIMITBUS, and INCREMENTBUS.

To view the Bus objects, open the Type Editor. In the Simulink® Toolstrip, on the Modeling tab, in the Design gallery, click Type Editor.

The model uses the Bus objects to specify the outputs of the following Bus Creator blocks:

  • COUNTERBUSCreator1

  • COUNTERBUSCreator2

  • LIMITBUSCreator1

  • LIMITBUSCreator2

  • IncrementBusCreator

The Inport block named counter_input in sldemo_mdlref_counter_bus specifies the Bus object named COUNTERBUS. Double-click the block. In the Block Parameters dialog box, on the Signal Attributes tab, Data type is set to Bus: COUNTERBUS.

The Inport block named increment_input is similarly configured to use the Bus object named INCREMENTBUS.

Log Signal Data

These signals are marked for signal logging:

  • COUNTERBUS

  • INCREMENTBUS

  • OUTERDATA

  • INNERDATA

After you simulate the model, the logged signals are available in the base workspace in the topOut variable.

topOut = 

Simulink.SimulationData.Dataset 'topOut' with 4 elements

                         Name          BlockPath                                
                         ____________  ________________________________________ 
    1  [1x1 Signal]      COUNTERBUS    sldemo_mdlref_bus/Concatenate           
    2  [1x1 Signal]      OUTERDATA     sldemo_mdlref_bus/CounterA              
    3  [1x1 Signal]      INCREMENTBUS  sldemo_mdlref_bus/IncrementBusCreator   
    4  [1x1 Signal]      INNERDATA     ...erA|sldemo_mdlref_counter_bus/COUNTER

  - Use braces { } to access, modify, or add elements using index.

The model uses Dataset format for signal logging. To access Dataset format logged data for a given signal, use the getElement method:

topOut.getElement('COUNTERBUS')
ans = 

  Simulink.SimulationData.Signal
  Package: Simulink.SimulationData

  Properties:
              Name: 'COUNTERBUS'
    PropagatedName: ''
         BlockPath: [1x1 Simulink.SimulationData.BlockPath]
          PortType: 'outport'
         PortIndex: 1
            Values: [2x1 struct]

Bus data is logged as a MATLAB® structure in the Values field:

topOut.getElement('COUNTERBUS').Values
ans = 

  2x1 struct array with fields:

    data
    limits

This structure contains MATLAB timeseries objects for each bus:

topOut.getElement('COUNTERBUS').Values(1).data
  timeseries

  Common Properties:
            Name: 'data'
            Time: [301x1 double]
        TimeInfo: tsdata.timemetadata
            Data: [301x1 int32]
        DataInfo: tsdata.datametadata


topOut.getElement('COUNTERBUS').Values(2).data
  timeseries

  Common Properties:
            Name: 'data'
            Time: [301x1 double]
        TimeInfo: tsdata.timemetadata
            Data: [301x1 int32]
        DataInfo: tsdata.datametadata

You can also plot the logged data using the plot function:

topOut.getElement('OUTERDATA').Values.plot()

Log Referenced Model Signals

To log signals in the referenced model, select the Model block and click Log Signals on the Model Block tab.

For this model, Logging Mode is set to Log all signals as specified in model. All the signals that are logged when simulating sldemo_mdlref_counter_bus as a top model are also logged when simulating it as a referenced model. To change logging for any of these signals or to log a subset of signals:

  1. Set Logging Mode to Override signals.

  2. In the Model Hierarchy pane, clear the CounterA (sldemo_mdlref_counter_bus) check box to indicate that this model should not use the Log all signals as specified in model setting.

  3. In the table, select the signals to log when simulating the top model.

  4. To save the changes, save the top model.

Load Data

Open the referenced model sldemo_mdlref_counter_bus as a top model by clicking the Open As Top Model badge at the lower left corner of the Model block.

The referenced model is configured to read the logged signal data through the root Inport blocks. To see this configuration, open the Configuration Parameters dialog box. In the Simulink Toolstrip, on the Modeling tab, click Model Settings. On the Data Import/Export tab, Input uses a comma-separated list to specify logged data from topOut for the two input ports. The counter_input port uses an array of structure of timeseries to load data for COUNTERBUS, and the increment_input port uses a structure of timeseries to load data for INCREMENTBUS.

  • topOut.getElement('COUNTERBUS')

  • topOut.getElement('INCREMENTBUS')

You can configure the Input field by clicking the Connect Inputs button. The Root Inport Mapper tool opens. In this example, the tool uses a mapping algorithm to set up the Input field from logged data in the base workspace.

To select the data to import:

  1. In the Root Inport Mapper, click From Workspace.

  2. Select the logged data topOut and click OK.

  3. In the dialog box that opens, specify a file name and click Save.

With the data loaded into the Root Inport Mapper tool, you can determine the root input port for which to assign input data. Simulink matches input data with input ports based on one of these criteria: block name, block path, signal name, port order, or a custom algorithm. Because topOut is logged using signal names from the model, the best choice for a mapping criterion is Signal Name. Using this criterion, Simulink tries to match input data variable names to the names of the input signals.

To select this option:

  1. In the Root Inport Mapper hierarchy pane, select scenario dataset topOut.

  2. Click Signal Name from the dropdown.

  3. Click the Check Map Readiness button arrow, then click Map All.

When mapping data, Simulink evaluates input ports against the input data to determine compatibility. The Root Inport Mapper table reflects the status of this compatibility with a green check mark, orange warning triangle, or red error exclamation mark. In this example, the table shows a green status indicating there is no compatibility issue. You can simulate the model with this mapping of input data to input ports. The mapping also sets Input in the Data Import/Export tab of the Configuration Parameters dialog to the proper comma-separated list of inputs. To apply the changes to the model, in the Configuration Parameters dialog, click Apply.

Simulate Model with Imported Data

Simulate sldemo_mdlref_counter_bus.

After simulation, the scopes from sldemo_mdlref_bus (OUTERDATA) and sldemo_mdlref_counter_bus (INNERDATA) show the same trace.

The signal feeding the scope in the referenced model is also logged. The logged data is available in the MATLAB workspace under the variable subOut. You can verify that the data in topOut.getElement('OUTERDATA') and subOut.getElement('INNERDATA') is the same.

See Also

Related Topics