National Instruments Data Acquisition Device E Series - Manual (Page 50)

Chapter 2 Analog Input
© National Instruments Corporation 2-17 E Series User Manual
If the buffer becomes full, the DAQ device continuously discards the oldest
samples in the buffer to make space for the next sample. You can access this
data (with some limitations) before the DAQ device discards it. Refer to the
KnowledgeBase document, Can a Pretriggered Acquisition be
Continuous?, for more information.
When the reference trigger occurs, the DAQ device continues to write
samples to the buffer until the buffer contains the desired number of
posttrigger samples. Figure 2-6 shows the final buffer.
Figure 2-6. Reference Trigger Final Buffer
Pre-Trigger Samples
Reference Trigger
Post-Trigger Samples
Complete Buffer