Logging Real-Time Test Data

NI VeriStand 2018 Help

Edition Date: May 2018

Part Number: 372846M-01

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You can use stimulus profiles to log real-time test data to the host computer while a test executes on a target. Logging test data enables you to easily review and save the responses of a unit under test (UUT) to specific scenarios. NI VeriStand saves logged data in the TDMS file format, which you can later view and analyze using the TDMS File Viewer workspace tool, other National Instruments software such as NI DIAdem, or Microsoft Excel. The Stimulus Profile Editor provides support for both triggered and segmented logging to help you manage large data sets and long test scenarios.

Note  This topic only applies to logging operations you execute in the Stimulus Profile Editor.
Tip  To walk through the creation of a stimulus profile that logs real-time test data with a fully functional example project, refer to the Getting Started with the Stimulus Profile Editor tutorial.

Complete the following steps to create a stimulus profile that logs real-time test data:

  1. Create a stimulus profile that calls a real-time sequence for which you want to log test results.
  2. Add a Start Logging step to the stimulus profile, before the Real-Time Sequence Call step. The step appears as Start Logging Configuration with a Channel Group substep.

  3. Select Start Logging Configuration in the stimulus profile code and use the Property Browser to configure the following properties:
    1. Configuration Name—The name you want to use to control the logging operation. You use this name to start and stop logging.
    2. File Path—The name and location for the resulting log file.
    3. Timestamp Filename—Whether to append the start time of the logging operation to the name of the log file.
    4. Replace Existing File—Whether to replace an existing file with the same filename. If you set this property to FALSE, the Stimulus Profile Editor appends any new log data to the existing file. This property performs a basic append, so you will need to use the channel data in the final file to determine where new data is appended.
      Tip  Add a time channel to your log to easily identify breaks in data logging.
    5. Log Rate [Hz]—The Stimulus Profile Editor logs data at the closest possible rate to this value without exceeding the rate at which the target produces data.
    6. (Optional) Triggered Logging—Configure trigger conditions to specify when data logging starts and stop. If you do not configure triggers, the Stimulus Profile Editor continuously logs all specified channel data beginning when the Start Logging step executes.
  4. Select the Channel Group step in the stimulus profile code and configure the following properties:
    1. Channel Group Name—The name of the channel group used in the TDMS file.
    2. Channels—Adds channels to the channel group. Click the Browse button to navigate to channels by path in the system definition or, if you defined aliases for the channels, by alias.
  5. (Optional) Add additional Channel Group steps under Start Logging Configuration in the stimulus profile code to log data in multiple channel groups.
  6. Add a Stop Logging step after the Real-Time Sequence Call step, and set the Configuration Name to exactly match the name you specified in the Start Logging step.

  7. Save and run the stimulus profile. The Stimulus Profile Editor logs data on the channels you specified, using the triggers and file segmenting you specify.

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