Fetching Data

Fetching data involves the following main steps:

  1. Declaring a waveform array (except in LabVIEW)
  2. Initiating an acquisition
  3. Waiting for the data acquisition to complete
  4. Retrieving data from the digitizer to your host computer

Advanced Fetching Options

NI-SCOPE supports several attributes for advanced fetching operations. The two following attributes are general purpose, allowing you to fetch only a portion of the acquired waveforms.

  • The Fetch Offset attribute is the offset in samples from which to start fetching samples. It may be negative.
  • The Fetch Relative To attribute specifies what the retrieval offset is relative to. All digitizers support fetching relative to pretrigger and trigger. The pretrigger sample is the first pretrigger point requested with the Configure Horizontal Timing function. This is the typical (and default) method because it allows fetching the exact data requested with the Configure Horizontal Timing function. Fetching relative to the trigger means the first posttrigger sample is the first one fetched. Digitizers supporting continuous acquisition have several other options for the Fetch Relative To attribute.