National Instruments cDAQ-9179, Руководство пользователя

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Chapter 4 Digital Input/Output and PFI
Digital Output Triggering Signals
Digital output supports two different triggering actions: DO Start Trigger and DO Pause Trigger.
A digital or analog trigger can initiate these actions. Any PFI terminal can supply a digital
trigger, and some C Series analog modules can supply an analog trigger. For more information,
refer to the documentation included with your C Series module(s).
Refer to the DO Start Trigger Signal and DO Pause Trigger Signal sections for more
information about the digital output trigger signals.
Digital Output Timing Signals
The cDAQ chassis features the following DO timing signals:
• DO Sample Clock Signal *
• DO Sample Clock Timebase Signal
• DO Start Trigger Signal *
• DO Pause Trigger Signal *
Signals with an * support digital filtering. Refer to the PFI Filters section for more information.
DO Sample Clock Signal
The DO Sample Clock (do/SampleClock) signals when all the digital output channels in the task
update. DO Sample Clock can be generated from external or internal sources as shown in
Figure 4-4.
Figure 4-4. Digital Output Timing Options
Routing DO Sample Clock to an Output Terminal
You can route DO Sample Clock to any output PFI terminal. DO Sample Clock is active high
by default.
Progr a mm ab le
Clock
Divider
DO Sa mple Clock
Time bas e
PFI
An a log Comp a ri s on Event
Ctr n Intern a l O u tp u t
DO Sa mple Clock
An a log Comp a ri s on
Event
20 MHz Time bas e
80 MHz Time bas e
PFI
100 kHz Time bas e