National Instruments Network Device DAQ S User Manual
Page 65
Chapter 6
Digital I/O
6-6
ni.com
Using an Internal Source
To use DO Sample Clock with an internal source, specify the signal source
and the polarity of the signal. The source can be any of the following
signals:
•
AI Sample Clock (ai/SampleClock)
•
AI Convert Clock (ai/ConvertClock)
•
AO Sample Clock (ao/SampleClock)
•
Counter n Internal Output
•
Frequency Output
•
DI Change Detection Output
Several other internal signals can be routed to DO Sample Clock through
RTSI. Refer to Device Routing in MAX in the NI-DAQmx Help or the
LabVIEW Help in version 8.0 or later for more information.
Using an External Source
You can route any of the following signals as DO Sample Clock:
•
PFI <0..15>
•
RTSI <0..7>
•
PXI_STAR
•
Analog Comparison Event (an analog trigger)
You can generate samples on the rising or falling edge of DO Sample
Clock.
You must ensure that the time between two active edges of DO Sample
Clock 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 DAQ device
reports an overrun error to the host software.
Routing DO Sample Clock to an Output Terminal
You can route DO Sample Clock out to any PFI terminal. The PFI circuitry
inverts the polarity of DO Sample Clock before driving the PFI terminal.