DDS Blockset Limitations and Considerations

R2026b

The Data Distribution Service (DDS) is a middleware standard for real-time publish-subscribe communication. DDS Blockset does not support the following import, modeling, simulation, and deployment capabilities.

Import DDS Definitions

When importing DDS definitions, DDS Blockset does not support:

  • DDS topics that use these data types:

    • Sequences

    • Arrays of strings

    • Multidimensional arrays

  • Specifying Quality of Service (QoS) profiles for domain participants, publishers, or subscribers.

  • RTI-specific tags in imported QoS XML files (these tags are ignored and are not included in generated XML).

For a list of supported IDL data types and semantics, see Import Considerations and Limitations.

Model DDS Applications

When modeling DDS applications, consider the following:

  • You must map all ports in an application model to DDS. If you have ports that do not map to DDS, the model does not simulate or build correctly.

  • When you export a DDS Blockset model to a previous version of MATLAB®, only the model file is exported. The associated Simulink® data dictionary file is excluded. You must manually add the data dictionary file to the exported model folder.

Simulate DDS Applications

DDS Blockset does not support these simulation features:

  • Accelerator mode — Speeds up simulation by generating and executing compiled target code while still using the normal simulation infrastructure for I/O and display.

  • Rapid accelerator mode — Provides the fastest simulation speed by creating a standalone executable that runs outside the Simulink environment.

  • MAT-file logging — Saves simulation output data directly to a MAT-file during model execution.

  • Software-in-the-loop (SIL) testing — Verifies generated source code by compiling and running it on the host computer within the Simulink environment.

For more information about simulation modes, see Choosing a Simulation Mode.

DDS Live Simulation

When using DDS Live Simulation (LiveSim), consider the following:

  • Timing Accuracy — The timing behavior of DDS Live Simulation does not strictly replicate real-world system timing. Variations can occur due to simulation abstractions and execution environment constraints.

  • Dependency on System and Network Performance — LiveSim performance depends on available computational resources (CPU, memory) and network layer efficiency. Variations in these factors can affect simulation responsiveness and timing consistency.

  • High-Frequency Modeling — For models operating at high execution frequencies, LiveSim can require additional processing time beyond the specified simulation duration. Higher-frequency workloads impose increased computational and communication overhead, which can extend simulation runtime.

  • RTI Connext Micro Vendor Support — DDS Live Simulation does not fully support the RTI Connext Micro vendor for live simulation. Using live simulation with RTI Connext Micro can lead to unexpected behavior.

Deploy DDS Applications

DDS Blockset does not support compiling the code generated from a DDS application model for a non-DDS application.

See Also

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