Table Of Contents

Creating Real-Time Sequences

Last Modified: June 10, 2021

Use real-time sequences to define specific tasks for a unit under test (UUT).

Before you begin, you should familiarize yourself with the Stimulus Profile Editor environment. Real-time sequences deploy to the target and can deterministically execute. Sequences test the UUT by reading from and writing to channels defined in the system definition file. These sequences can include a wide variety of programming constructs, including while loops, for loops, variables, and conditional statements.

Real-time sequences appear on the VeriStand Editor in the Project Files tab with the file extension .nivsseq. A real-time sequence cannot execute on its own and must belong to a stimulus profile.

  1. In the VeriStand Editor, click Tool Launcher»Stimulus Profile Editor.
  2. In the Stimulus Profile Editor, click File»New»Real-Time Sequence. The sequence organizes your code into the Setup, Main, and Clean Up blocks. The Primitives palette contains programming building blocks, such as statements and variables, you can use to define the task the real-time sequence completes.
  3. Create the variables your sequence code can access.
    1. Drag variables from the Primitives palette to one of the following sections of the Variables pane.
      Section Description
      Return Variable The value the real-time sequence returns after it executes.
      Parameters The inputs and outputs that the sequence accepts when called and can pass out to other sequences or the stimulus profile.
      Local Variables Variables you want to access from statements within the current sequence.
      Channel References References that allow you to read/write system definition channels directly from a real-time sequence.
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      Note  

      Channel references bind to specific system definition channels when added to a real-time sequence. The sequence that contains them is bound to that system definition file. If you want to write a sequence that you can reuse across multiple system definition files, use Parameters.

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      Note  

      Use Double or Boolean primitives to create parameters that you want to map to system definition channels. All channels in VeriStand are 64-bit floating point numbers (doubles), but many can also accept Boolean values.

    2. To add channel references, right-click Channel References and click Insert Channels.
  4. Map parameters to system definition channels.
    1. Select a parameter in the Variables pane.
    2. In the Property Browser, give the parameter a unique Identifier.
    3. Next to Default Assignment, click Browse and navigate to the appropriate channel or click View aliases in the window to select a channel by its alias.
  5. If you want to use Local Variables in statements or expressions, use the Property Browser to configure a unique Identifier and a Default Value for those variables
  6. If you want to call another sequence from an expression in the current sequence, add the new sequence to the References pane. You can drag variables from the Variables pane or sequences from the Sequences palette directly to the sequence code to automatically create expressions that act on those elements. In the case of sequences, VeriStand also creates references to the sequence.
  7. Use expressions, structures, and other primitives to build the sequence code. Select any item in the sequence code to configure it in the Property Browser.
  8. Click Compile.
    1. Resolve any Warnings and Errors.
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      Note  

      A sequence can run with warnings, but not errors. You can save the profile and resolve errors later.

  9. Save the sequence.

After creating the real-time sequence, add a call for the real-time sequence to a stimulus profile. A sequence cannot execute independently of a stimulus profile. Run the stimulus profile to run the sequence.


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