LabVIEW provides some NI-SCOPE examples, which you can use for quick development. Below is a modified version of the example "niSxope EX Fetch Forever.vi". It uses an external signal on PFI1 as a start trigger.

Note: This image is a LabVIEW snippet, which includesLabVIEW code that you can reuse in your project. To use a snippet, right-click the image, save it to your computer, and drag the file onto your LabVIEW diagram.