Ai Sample Clock Timebase Signal - National Instruments PCIe-6323 User Manual

• PXIe_DSTAR<A,B>
• Analog Comparison Event (an analog trigger)
Note (NI PXIe-6386/6396 Devices)
several ways from other SMIO devices. For more information about using an external
source with these devices, go to
Routing AI Sample Clock Signal to an Output Terminal
You can route AI Sample Clock out to any PFI <0..15>, RTSI <0..7>, or PXIe_DSTARC
terminal. This pulse is always active high.
All PFI terminals are configured as inputs by default.
Other Timing Requirements
Your DAQ device only acquires data during an acquisition. The device ignores AI Sample Clock
when a measurement acquisition is not in progress. During a measurement acquisition, you can
cause your DAQ device to ignore AI Sample Clock using the AI Pause Trigger signal.
A counter/timing engine on your device internally generates AI Sample Clock unless you select
an external source. AI Start Trigger starts this counter and either software or hardware can stop
it once a finite acquisition completes. When using the AI timing engine, you can also specify a
configurable delay from AI Start Trigger to the first AI Sample Clock pulse. By default, this
delay is set to two ticks of the AI Sample Clock Timebase signal.
Figure 4-30 shows the relationship of AI Sample Clock to AI Start Trigger.

AI Sample Clock Timebase Signal

You can route any of the following signals to be the AI Sample Clock Timebase
(ai/SampleClockTimebase) signal:
• 100 MHz Timebase (default)
• 20 MHz Timebase
Figure 4-30. AI Sample Clock and AI Start Trigger
AI Sample Clock Timebase
AI Start Trigger
AI Sample Clock
PXIe-6386 and PXIe-6396 devices differ in
and enter the Info Code
ni.com/info
Delay
From
Start
Trigger
X Series User Manual
smio14ms
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