Using An Internal Source; Using An External Source; Digital Waveform Acquisition (Ni 6731/6733 Only) - National Instruments NI 6711 User Manual

Digital Waveform Acquisition (NI 6731/6733 Only)

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Using an Internal Source

To use do/SampleClock with an internal source without making any
external connections, specify the signal source and the polarity of the
signal. The source can be one of the following signals:
• AO Sample Clock
• Counter 0 Out
Program the DAQ device to update the DIO pins on the rising edge or
falling edge of do/SampleClock.

Using an External Source

You can use a signal connected to any RTSI <0..6> pin as the source of
do/SampleClock. You can generate samples on the rising or falling edge of
do/SampleClock.
Any PFI line that can be routed to RTSI can also be used as the clock
source. Refer to Device Routing in MAX in the NI-DAQmx Help or the
LabVIEW Help in version 8.0 for more information.
You must ensure that the time between two active edges of the
do/SampleClock is not too short. If the time is too short, the DO waveform
generation FIFO is not able to read the next sample fast enough.
The NI 6731/6733 can acquire digital waveforms. This behavior is also
referred to as correlated digital I/O because there is no dedicated clock
source for the digital operation. Refer to the
(NI 6731/6733 Only)
The DI waveform acquisition FIFO stores the digital samples. The
NI 6731/6733 can use DMA transfers to move data from the DI waveform
acquisition FIFO to system memory. The DAQ device samples the DIO
lines on each rising or falling edge of a clock signal, di/SampleClock. For
more information on DMA transfers, refer to the
(DMA) section of Chapter 9,
You can configure each DIO line to be an output, a static input, or a digital
waveform acquisition input.
section for a list of possible sources.
Bus Interface.
4-3
Chapter 4
DI Sample Clock Signal
Direct Memory Access
Analog Output Series User Manual
Digital I/O