MATLAB: Does acquiring the parameter BusStruct cause MATLAB to crash

simulink

In my model I have a block that tries to get the parameter 'BusStruct' during the 'InitFcn' callback. However, when I try to update the model MATLAB crashes. Why does this occur?

Best Answer

The parameter 'BusStruct' is an undocumented parameter. In the past, with the property 'BusStruct', users were able to get the hierarchical structure of a bus signal from a BusSelector or BusCreator block in a Simulink model after model update diagram (Ctrl+D).

You would select, for instance, a BusSelector block in your model, and type in MATLAB command window. For testing you can open demo Simulink model busdemo.slx :

tmp = get_param(gcbh,'BusStruct')  % Command is undocumented and can be deprecated in future releases!
ans = 
  2×1 struct array with fields:
    name
    src
    srcPort
    signals

Using 'BusStruct' property is not a recommended workflow. Instead, you could look at the 'SignalHierarchy' for the bus to obtain similar information. The example found under the section 'Bus Signal Example' in the link below demonstrates how to get this information.

https://www.mathworks.com/help/simulink/ug/view-composite-signals.html?searchHighlight=view%20composite%20signal&s_tid=srchtitle

Related Solutions

MATLAB: How to retrieve names of signals in a bus when the signal names have been propagated by Simulink

This enhancement has been incorporated in Release 2010a (R2010a). For previous product releases, read below for any possible workarounds:

The ability to use a command-line command to retrieve the names of propagated signals in a bus signal is not available in Simulink.

To work around this issue, use the following code:

busdemo
ph = get_param('busdemo/Bus Creator', 'porthandles')
set_param(ph.Outport, 'CacheCompiledBusStruct', 'on')
busdemo([],[],[],'compile')
bs = get_param(ph.Outport, 'CompiledBusStruct')
busdemo([],[],[],'term')

The variable 'bs' will contain information on the bus signal coming out of the Bus Creator. You can recursively walk through this structure to determine all actual sources of the bus and hence all source data types, dimensions, signal names, etc.

Note that the following code makes use of the internal compiled property 'CacheCompiledBusStruct' and hence is subject to change in future releases.

Another workaround to retrieve the names of signals in a bus is to pass all the Bus Creator outputs to a Bus Selector block, which selects all of the signals from the Bus Creator block, then use the following code to extract the signal names, where the Bus Selector block is the currently selected block:

get_param(gcb, 'OutputSignals')

MATLAB: Importing legacy models from created with MIT Toolbox

Yes, the models created and which were working with MIT Toolbox can be used with the Simulink Support package for PARROT Minidrones, provided they follow the steps below:

1. Update the existing model to be used with Buses and 4 ports. It is mandatory to have the these 4 ports and signals through them as specified below:

Specifications of root level ports and signals through them

* Sl. No Port Type Data Type Storage class for signal through it Size Alias

*1. Inport (AC cmd) Bus: CommandBus ExportedGlobal NA Cmd_inport

* *2. Inport (Sensors) Bus: SensorsBus ExportedGlobal NA sensor_inport

* *3. Outport (Actuators) double ExportedGlobal 4 motors_outport

* *4. Outport (Flag) Uint8 ExportedGlobal 1 flag_outport

2. You can copy paste the controller logic from the old model and update the signals in such a way that the above criteria are met.

3. If simulation works and is successful, proceed to build the model.

Best Answer

Related Solutions

MATLAB: How to retrieve names of signals in a bus when the signal names have been propagated by Simulink

MATLAB: Importing legacy models from created with MIT Toolbox

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