Create Nonvirtual Buses Within Component

You can use Bus Creator blocks to create nonvirtual buses within components.

Open and compile the model named BusHierarchy, which uses Bus Creator blocks to create a hierarchy of virtual buses. To compile the model, on the Modeling tab of the Simulink® Toolstrip, click Update Model or Run. Compiling the model updates the line styles, which you can use to visually identify buses.

mdl = BusHierarchy;
open_system(mdl)
set_param(mdl,SimulationCommand="Update")

To create this model, see Group Signal Lines Within Component.

The virtual buses in this model are not defined by Simulink.Bus objects. To change the output of the Bus Creator blocks to nonvirtual buses, you must have bus objects that match the bus hierarchy.

To create the bus objects that correspond to TopBus and NestedBus, use the Simulink.Bus.createObject function. In the MATLAB® Command Window, enter this command.

Simulink.Bus.createObject("BusHierarchy","BusHierarchy/Bus Creator1");

This function creates the bus object that corresponds to the output bus of the specified block. If the output bus contains nested buses, the function also creates bus objects that correspond to the nested buses. In this example, the function creates two bus objects that are named after the corresponding buses, TopBus and NestedBus.

To view the bus objects, open the Type Editor. In the Simulink Toolstrip, on the Modeling tab, in the Design gallery, click Type Editor. To expand an external data source or bus, click the arrow next to its name.

Now that you have bus objects that correspond to the nonvirtual buses you want to create, create the nonvirtual buses. In the Simulink Editor, double-click the Bus Creator block named Bus Creator1. In the Block Parameters dialog box, set Output data type to Bus: TopBus, select the Output as nonvirtual bus check box, and click OK. TopBus is now a nonvirtual bus, while NestedBus remains a virtual bus. To identify the nonvirtual bus by line style, compile the model.

Double-click the block named Bus Creator. In the Block Parameters dialog box, set Output data type to Bus: NestedBus, select the Output as nonvirtual bus check box, and click OK. NestedBus is now a nonvirtual bus. To update its line style, compile the model.

If you do not save the bus objects, then you must recreate the bus objects when you reopen the model. For information on how to save the bus objects, see Specify Bus Properties with Bus Objects.

Create Nonvirtual Buses at Interfaces

To create a nonvirtual bus at an interface, connect the bus elements to Out Bus Element blocks and specify that the output bus is nonvirtual.

Open the model named BusOutput, which uses three Out Bus Element blocks to create a virtual bus at the output port.

To create this model, see Connect Multiple Output Signals to a Port.

Nonvirtual buses require a Simulink.Bus object data type. Create the bus object that corresponds to the output bus.

To output a nonvirtual bus, specify the bus object data type and bus virtuality.

The output of the model is a nonvirtual bus. To see the nonvirtual bus, reference the model in another model or move the Out Bus Element blocks into a subsystem. The line styles update when you compile the model. To compile the model, on the Modeling tab of the Simulink Toolstrip, click Update Model or Run.

If you do not save the bus objects, you must recreate the bus objects when you reopen the model. For information on how to save the bus objects, see Specify Bus Properties with Bus Objects.

In Bus Element blocks use the Bus virtuality parameter to determine whether they inherit or define the bus virtuality. If the block defines the bus virtuality and the virtuality of the input bus does not match, compiling the model produces an error.

Root Inport and Outport blocks can also create nonvirtual buses at interfaces. To specify the bus virtuality:

Convert Virtual Bus to Nonvirtual Bus

You can convert a virtual bus to a nonvirtual bus anywhere within a model by using a Signal Conversion block.

Open and compile the model named BusConversion, which contains a virtual bus hierarchy created by Bus Creator blocks. To compile the model, on the Modeling tab of the Simulink Toolstrip, click Update Model or Run. Compiling the model updates the line styles, which you can use to visually identify buses.

To define the buses and support conversion to nonvirtual buses, the Bus Creator blocks specify Simulink.Bus object data types. To create the bus objects in the base workspace when the model is loaded, the model uses the PreLoadFcn callback.

To view the callback, in the Simulink Toolstrip, on the Modeling tab, click Model Settings > Model Properties. In the Model Properties dialog box, open the Callbacks tab and select the PreLoadFcn model callback.

To view the bus objects, open the Type Editor.

To convert a virtual bus to a nonvirtual bus, use a To Nonvirtual Bus block, which is a preconfigured version of the Signal Conversion block that has Output set to Nonvirtual bus.

In the example model:

Suppose the data type of the bus you want to convert is not specified by a bus object. You would need to perform these additional actions:

The input to the To Nonvirtual Bus block is a virtual bus, and the output is a nonvirtual bus. To see the nonvirtual bus line style, compile the model.

Create Nonvirtual Bus from MATLAB Structure

You can use a Constant block to compactly represent a nonvirtual bus with constant-valued elements.

On the Constant block, specify:

Constant blocks only support MATLAB structures when the output data type is a Bus object.

For example, define a MATLAB structure named const_param_struct with elements named Offset, Gain, and Threshold.

const_param_struct.Offset = 197;
const_param_struct.Gain = 4.32;
const_param_struct.Threshold = 795.68;

Define the corresponding Bus object data type.

Simulink.Bus.createObject(const_param_struct)

The new Bus object uses the default name slBus1.

Open and simulate the example model, which contains a Constant block with Constant value set to const_param_struct and Output data type set to Bus: slBus1.

open_system('NonvirtualBusFromStructModel')
sim('NonvirtualBusFromStructModel');

The output of the Constant block is a nonvirtual bus.