ADLINK PXIe-9848 - Manual (Page 34)

24 Operations
3.4.3 Middle-trigger Mode
Used to collect data before and after the trigger event. The amount
of stored data before and after trigger event can be set individually
(M and N samples), as follows.
Figure 3-9: Middle-trigger Acquisition
3.4.4 Delayed Trigger Mode
Delayed-trigger acquisition is utilized to postpone data collection
after the trigger event, as shown. When PXIe-9848 receives a trig-
ger event, a time delay is implemented before commencing acqui-
sition. The delay is specified by a 16-bit counter value such that a
maximum thereof is the period of TIMEBASE X (2
32
), and the min-
imum is the Timebase period.
Figure 3-10: Delayed Trigger Mode Acquisition
NOTE: NOTE:
Trigger events can only be accepted when the specified
amount of data has been acquired (M samples) since opera-
tion start. If the sampled data is insufficient, the trigger event
will be ignored.
Time
Operation start
Acquisition start
Trigger
Data
Acquisition stop
Data transfer to system begins
N samples M samples
Trigger Event occurs