Real-Time Operating Systems (Real-Time Module)

NI designed the LabVIEW Real-Time Module to execute VIs on three different real-time operating systems: Phar Lap ETS, Wind River VxWorks, and NI Linux Real-Time. However, special considerations must be made when working with these real-time operating systems.

Modifying Front Panel Objects of RT Target VIs

When a VI or stand-alone application runs on a headless RT target or if you disable the embedded UI, you cannot execute VIs that modify a front panel. For example, you cannot change or read the properties of front panel objects with property nodes because there is no front panel for VIs that run on the RT target. The VI still runs on the RT target but the front panel object is not affected and returns an error. In some cases, you can establish a front panel connection with the RT target to use some unsupported LabVIEW features. Right-click an RT target in the Project Explorer window and select Connect from the shortcut menu to open a front panel connection with the target.

The following features only work on an RT target with a front panel connection:

  • Front panel property nodes and control references.
    Note  An RT target updates the values of property nodes and control references asynchronously, meaning a property node or control reference might not contain the latest value of the indicator or control.
  • Dialog VIs and functions
  • VI Server front panel functions
Note  Some LabVIEW example VIs use unsupported VIs and functions and do not execute on an RT target.

Real-Time Module and Express VI Considerations

LabVIEW Express VIs increase LabVIEW ease of use and improve productivity with interactive dialog boxes that minimize programming for measurement applications. Express VIs require additional performance overhead during execution; therefore, do not use Express VIs in deterministic or processor-intensive applications. Instead, develop real-time applications with standard LabVIEW VIs.

Debugging Reentrant VIs

LabVIEW debugging tools are not available for copies of reentrant VIs executing on RT targets. Because LabVIEW identifies copies of reentrant VIs by their front panels and VIs executing on RT targets do not include front panels, LabVIEW cannot open reentrant VI copies for debugging. However, you can run and debug your application on Windows prior to deploying the application to the RT target.

Working with the Different Real-Time Operating Systems

Refer to the following topics to learn about unique considerations and unsupported features for each real-time operating system:

Refer to the specific RT target hardware documentation for information about the real-time operating system installed on the target.


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