How can I load a personalized QoS profile in RTI DDS Toolkit for LabVIEW?

Submitted by sara on Wed, 05/29/2013 - 07:20

QoS profiles provide a way to configure your DDS application, defining most aspects of the DDS paradigm and the underlying communication mechanisms. As part of RTI DDS Toolkit for LabVIEW we provide a set of pre-defined QoS profiles. These profiles solve general use cases such as a Reliable Communication or including the RTI Monitoring libraries. They can be found in the default QoS XML file ( RTI_LABVIEW_CONFIG.xml) provided with the toolkit.

Note: The default QoS configuration file can be found under C:/Program Files (x86)/National Instruments/LabVIEW 2012/vi.lib/_RTI DDS Toolkit for LabVIEW _internal_deps/RTI_LABVIEW_CONFIG.xml

These profiles are illustrative and might not fullfill all the desired functionalities. To adjust them to your needs, you can create your own XML configuration file (for instance, USER_QOS_PROFILES.xml). You can define several libraries and profiles in each unique XML file and use their names to reference them in the subVI calls (for instance,  LabVIEWLibrary::DefaultProfile references to the DefaultProfile from RTI_LABVIEW_CONFIG.xml). Once you have defined the QoS settings you need and stored them in a file (or files), the RTI DDS Tookit for LabVIEW will load it automatically if you point it to the correct file. There are two different options to do so:

  1. Environment variable NDDS_QOS_PROFILES(recommended): you can define this environment variable to point to the correct XML files you want to load. You can specify multiple XML profiles separating them by semi-colons (;). Profile and library names need to be unique, so make sure they are not repeated among the different XML files. If you need to indicate several  locations for a single XML file (to differentiate between desktop and Real-Time target installations, for instance) you can use URL groups.
    For example: export NDDS_QOS_PROFILES = [file://C:/DDS_config/USER_QOS_PROFILES.xml | file:///home/lv_user/DDS_config/alternative_default_dds.xml]; file://C:/another_DDS_config/MY_QOS_PROFILE.xml. This example will load two XML files: either USER_QOS_PROFILES.xml or alternative_default_dds.xml and  MY_QOS_PROFILE.xml.
  2. Working directory (not recommended): you can save a file called USER_QOS_PROFILES.xml in the working directory of LabVIEW.

Note: The working directory in LabVIEW depends on the application kind. If you are running a VI from LabVIEW, the working directory is the one of the LabVIEW.exe file, i. e. C:/Program Files (x86)/National Instruments/LabVIEW 2012/. On the other hand, if your application is an independent one, it will use the Run-Time Engine to execute and the working directory will be C:/Program Files (x86)/National Instruments/Shared/LabVIEW Run-Time/2012/. In linux, the working directory points to /home/<user>

We strongly recommend the first approach that allows for a more versatile solution.

For more information see the following links:

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