National Instruments NI USB-6009 User Manual

Page of 32
NI USB-6008/6009 User Guide and Specifications
20
ni.com
Figure 11.  Connecting a Reference Single-Ended Voltage Signal
Digital Trigger
When an AI task is defined, you can configure PFI 0 as a digital trigger 
input. When the digital trigger is enabled, the AI task waits for a rising or 
falling edge on PFI 0 before starting the acquisition. To use ai/Start Trigger 
with a digital source, specify PFI 0 as the source and select rising or falling 
edge.
Analog Output
The NI USB-6008/6009 has two independent AO channels that can 
generate outputs from 0–5 V. All updates of AO lines are software-timed.
Analog Output Circuitry
Figure 12 illustrates the analog output circuitry for the NI USB-6008/6009. 
Figure 12.  Analog Output Circuitry
AI
NI USB-6008/6009
GND
Voltage
Source
REF(+) REF(–)
12-Bit
DAC
Output
Buffer
50
 Ω
AO
+5 V
GND