Chapter 4
Analog Input
4-38
ni.com
When the reference trigger occurs, the DAQ device continues to write
samples to the buffer until the buffer contains the number of posttrigger
samples desired. Figure 4-23 shows the final buffer.
Figure 4-23.
Reference Trigger Final Buffer
Using a Digital Source
To use ai/ReferenceTrigger with a digital source, specify a source and an
edge. The source can be any of the following signals:
•
PFI <0..15>
•
RTSI <0..7>
•
PXI_STAR
The source also can be one of several internal signals on your DAQ device.
Refer to
Device Routing in MAX
in the
NI-DAQmx Help
or the
LabVIEW
Help
in version 8.0 or later for more information.
You also can specify whether the measurement acquisition stops on the
rising edge or falling edge of ai/ReferenceTrigger.
Using an Analog Source
When you use an analog trigger source, the acquisition stops on the first
rising edge of the Analog Comparison Event signal.
Routing AI Reference Trigger Signal to an Output
Terminal
You can route ai/ReferenceTrigger out to any PFI <0..15> or RTSI <0..7>
terminal.
All PFI terminals are configured as inputs by default.
Reference Trigger
Pretrigger Samples
Complete Buffer
Posttrigger Samples