User Guide

© National Instruments Corporation 31 NI cDAQ-9172 User Guide and Specifications
Analog Output Timing Signals
The NI cDAQ-9172 chassis features the following AO (waveform
generation) timing signals:
• AO Sample Clock
•AO Start Trigger
• AO Pause Trigger
AO Sample Clock
The AO sample clock (ao/SampleClock) signals when all the analog output
channels in the task update. ao/SampleClock can be generated from
external or internal sources.
Figure 12. Analog Output Timing Options
Routing AO Sample Clock to an Output Terminal
You can route ao/SampleClock to any output PFI terminal.
AO Sample Clock Timebase Signal
The AO Sample Clock Timebase (ao/SampleClockTimebase)
signal is divided down to provide a source for ao/SampleClock.
ao/SampleClockTimebase can be generated from external or internal
sources, and is not available as an output from the chassis.
AO Start Trigger Signal
Use the AO Start Trigger (ao/StartTrigger) signal to initiate a waveform
generation. If you do not use triggers, you can begin a generation
with a software command. If you are using an internal sample clock,
you can specify a delay from the start trigger to the first sample. For
Analog Comparison
Event
20 MHz Timebase
100 kHz Timebase
Programmable
Clock
Divider
ao/SampleClock
Timebase
PFI
Analog Comparison Event
Ctr
n Internal Output
ao/SampleClock
PFI