National Instruments Eight-slot USB Chassis NI cDAQ-9172 - Manual (Page 37)

© National Instruments Corporation 37 NI cDAQ-9172 User Guide and Specifications
Using an Internal Source
To use di/SampleClock with an internal source, specify the signal source
and the polarity of the signal. Use the following signals as the source:
• AI Sample Clock
• AI Convert Clock
• AO Sample Clock
• Counter n Internal Output
• Frequency Output
• DI Change Detection Output
Several other internal signals can be routed to di/SampleClock. Refer to the
Device Routing in MAX topic in the NI-DAQmx Help or the LabVIEW Help
in version 8.0 or later for more information.
The NI-DAQmx Help is available after installation from Start»
All Programs»National Instruments»NI-DAQ»NI-DAQmx Help.
To view the LabVIEW Help, in version 8.0 or later, select Help»
Search the LabVIEW Help in LabVIEW. Alternately, to download
the LabVIEW Help, go to
ni.com/manuals .
Using an External Source
You can route the following signals as di/SampleClock:
• Any PFI terminal
• Analog Comparison Event (an analog trigger)
You can sample data on the rising or falling edge of di/SampleClock.
Routing DI Sample Clock to an Output Terminal
You can route di/SampleClock to any output PFI terminal. The PFI
circuitry inverts the polarity of di/SampleClock before driving the PFI
terminal.
Digital Waveform Generation (Correlated Output)
With a hardware-timed generation, a digital hardware signal controls the
rate of the generation. This signal can be generated internally on the chassis
or provided externally.
Hardware-timed generations have several advantages over software-timed
acquisitions:
• The time between samples can be much shorter.
• The timing between samples can be deterministic.
Hardware-timed operations must be buffered.