Attach Bus Signals to MATLAB Function Blocks
For an example of how to use structures in a MATLAB Function block, open the model emldemo_bus_struct.
In this model, a MATLAB Function block receives
a bus signal using the structure inbus at input
port 1 and outputs two bus signals from the structures outbus at
output port 1 and outbus1 at output port 2. The
input signal comes from the Bus Creator block MainBusCreator,
which bundles signals ele1, ele2,
and ele3. The signal ele3 is
the output of another Bus Creator block SubBusCreator,
which bundles the signals a1 and a2.
The structure outbus connects to a Bus Selector block BusSelector1;
the structure outbus1 connects to another Bus
Selector block BusSelector3.
To explore the MATLAB® function fcn,
double-click the MATLAB Function block. Notice that
the code implicitly defines a local structure variable mystruct using
the struct function, and uses
this local structure variable to initialize the value of the first
output outbus. It initializes the second output outbus1 to
the value of field ele3 of structure inbus.
Structure Definitions in Example
Here are the definitions of the structures in the MATLAB Function block in the example, as they appear in the Ports and Data Manager:
Bus Objects Define Structure Inputs and Outputs
Each structure input and output must be defined by a Simulink.Bus object in
the base workspace (see Create Structures in MATLAB Function Blocks). This means
that the structure shares the same properties as the bus object, including number, name,
type, and sequence of fields. In this example, the following bus objects define the
structure inputs and outputs:
The Simulink.Bus object MainBus defines structure input
inbus and structure output outbus. The
Simulink.Bus object SubBus defines structure output
outbus1. Based on these definitions, inbus and
outbus have the same properties as MainBus and,
therefore, reference their fields by the same names as the fields in
MainBus, using dot notation (see Index Substructures and Fields). Similarly, outbus1
references its fields by the same names as the fields in SubBus. Here are
the field references for each structure in this example:
| Structure | First Field | Second Field | Third Field |
|---|---|---|---|
inbus | inbus.ele1 | inbus.ele2 | inbus.ele3 |
outbus | outbus.ele1 | outbus.ele2 | outbus.ele3 |
outbus1 | outbus1.a1 | outbus1.a2 | — |