National Instruments Data Acquisition Device E Series - Manual (Page 51)

Chapter 2 Analog Input
E Series User Manual 2-18 ni.com
Using a Digital Source
To use ai/ReferenceTrigger with a digital source, specify a source and an
edge. The source can be an external signal connected to any PFI or
RTSI <0..6> pin. The source can also be one of several internal signals on
your DAQ device. Refer to Device Routing in MAX in the NI-DAQmx Help
or the LabVIEW 8.x Help for more information.
Also, specify whether the measurement acquisition stops on the rising edge
or falling edge of the ai/ReferenceTrigger signal.
Figure 2-7 shows the timing requirements of the ai/ReferenceTrigger
source.
Figure 2-7. ai/ReferenceTrigger Source Timing Requirements
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. Refer to the
Triggering
with an Analog Source section of Chapter 10, Triggering , for more
information on analog trigger sources.
Outputting the AI Reference Trigger Signal
You can configure the PFI 1/AI REF TRIG pin to output the
ai/ReferenceTrigger signal. The output pin reflects the ai/ReferenceTrigger
signal regardless of what signal you specify as its source.
Rising-Edge
Polarity
Falling-Edge
Polarity
t
w
t
w
= 10 ns minimum