National Instruments 6711 User Manual

Also see for DAQCard-6715: User manual User manual

Contents

National Instruments 6711 User Manual Manual pdf 36 page image

3-8 | ni.comChapter 3 Analog OutputOutputting the AO Sample Clock SignalYou can configure the PFI 5/AO SAMP CLK pin to output the ao/SampleClock signal. Theoutput pin reflects the ao/SampleClock signal regardless of what signal you specify as its source.The output is an active high pulse. Figure 3-7 shows the timing behavior of the PFI 5/AO SAMPCLK pin when the pin is an output.Figure 3-7. PFI 5/AO SAMP CLK as an OutputThe PFI 5/AO SAMP CLK is configured as an input by default.Other Timing RequirementsA counter on your device internally generates ao/SampleClock unless you select some externalsource. The ao/StartTrigger signal starts this counter. It is stopped automatically by hardwareafter a finite acquisition completes or manually through software. When using an internallygenerated ao/SampleClock in NI-DAQmx, you can also specify a configurable delay from theao/StartTrigger to the first ao/SampleClock pulse. By default, this delay is two ticks of theao/SampleClockTimebase signal.Figure 3-8 shows the relationship of the ao/SampleClock signal to the ao/StartTrigger signal.Figure 3-8. ao/SampleClock and ao/StartTriggertw = 50–75 nstwao/StartTriggerao/SampleClockao/SampleClockTimebaseDelayfromStartTrigger