ADLINK DAQe-2006 - Manual (Page 50)

38 Operation Theory
Figure 4-4: Pre-trigger
Note that If the trigger event occurs when a conversion is in
progress, the data acquisition will not stop until this conversion is
completed and the stored M scans of data include the last scan,
as illustrated in Figure 4-5, where M_counter = M = 3,
PSC_counter = 0.
Figure 4-5: Pre-trigger Scan Acquisition