ADLINK Technology PXIe-9834, User Manual, Page: 44 / 65

32 Operations
Leading
EDGE COMPUTING
3.4.2 Delayed Trigger Mode
Delayed-trigger acquisition is utilized to postpone data collection
after the trigger event, as shown. When the PXIe-9834 receives a
trigger event, a time delay is implemented before commencing
acquisition. The delay is specified by a 16-bit counter value such
that a maximum thereof is the period of TIMEBASE X (2
16
), and
the minimum is the timebase period.
Figure 3-8: Delayed Trigger Mode Acquisition
3.4.3 Pre-Trigger Mode
Collects data before the trigger event, starting once specified func-
tion calls are executed to begin the pre-trigger operation, and
stopping when the trigger event occurs. If the trigger event occurs
after the specified amount of data has been acquired, the system
stores only data preceding the trigger event by a specified
amount, as follows.
Figure 3-9: Pre-Trigger Mode Acquisition
Operation
Start Trigger Event Occurs Acquisition Stop
Time
N Samples
Trigger
Data
Acquisition Start
Delay Time
Time
Operation start
Acquisition start
Trigger
Data
Trigger Event Occurs
Acquisition stop
Data transfer to system begins
N samples
X samples have been acquired
before trigger occurs, where X<N
Trigger signals occuring before the specified
amount of data has been acquired are ignored