Measurement Computing Data Translation DT3010 Series, User Manual, Page: 116 / 232

Principles of Operation
115
Note: If you are using an analog threshold trigger to trigger both the A/D and the D/A
subsystems, ensure that you use the same analog trigger type for both subsystems (either
external or one of the analog input channels). The polarity of the triggers, however, can be
different.
Trigger Acquisition Modes
DT3010 Series boards can acquire data in post-trigger mode, pre-trigger mode, or
about-trigger mode. These trigger acquisition modes are described in more detail in the
following subsections.
Post-Trigger Acquisition
Use post-trigger acquisition mode when you want to acquire data when a post-trigger or
retrigger, if using triggered scan mode, occurs.
Using software, specify the following parameters:
• The dataflow as Continuous.
• The trigger source to start the post-trigger acquisition (the post-trigger source) as any of
the supported trigger sources.
Refer to page 110 for more information on the supported conversion modes; refer to page 113
for information on the supported trigger sources.
Post-trigger acquisition starts when the board detects the post-trigger event and stops when
the specified number of post-trigger samples has been acquired or when you stop the
operation.
If you are using triggered scan mode, the board continues to acquire post-trigger data using
the specified retrigger source to clock the operation. Refer to
page 111 for more information on
triggered scan mode.
Figure 57 illustrates continuous post-trigger mode using a channel list with three entries:
channel 0, channel 1, and channel 2. Triggered scan mode is disabled. In this example,
post-trigger analog input data is acquired on each clock pulse of the A/D sample clock. The
board wraps to the beginning of the channel list and repeats continuously
(continuously-paced scan mode).
Figure 57: Continuous Post-Trigger Mode without Triggered Scan
Post-trigger event occurs
Chan 0
Chan 1
Chan 2 Chan 0
Chan 1
Chan 2 Chan 0
Chan 1
Chan 2 Chan 0
Chan 1
Chan 2
A/D
Sample
Clock
Post-trigger data
acquired continuously