| Use Low Impedance Sources—To ensure fast settling times, your signal sources should
have an impedance of <1 kΩ. Large source impedances increase the settling time of the
NI DAQ device and decrease the accuracy at fast scanning rates. For more information
about decreasing the source impedance of an analog signal, go to
ni.com/info
and enter
the Info Code
rdbbis
.
•
Use Short High-Quality Cabling—Using short high-quality cables can minimize several
effects that degrade accuracy including crosstalk, transmission line effects, and noise. The
capacitance of the cable also can increase the settling time.
•
Avoid Scanning Faster Than Necessary—Design your system to scan at slower speeds
to give the NI DAQ device more time to settle to a more accurate level when switching
between channels.
AI Start Trigger
You can configure PFI 0 or PFI 1 as the AI Start Trigger for analog input tasks. Refer to the
Using PFI to Trigger an Analog Input Acquisition
section for more information.
Analog Output
Figure 11 shows the analog output circuitry of the NI USB-6001/6002/6003.
Figure 11.
Analog Output Circuitry
AO Data
AO Sampling Clock
AO Start Trigger
AO FIFO
Buffer
DAC 0
Protection
Buffer
DAC 1
Protection
AO 1
AO GND
AO 0
16-Position
Screw Terminal
Plug
I/O Connector
DAC
Control
NI USB-6001/6002/6003 User Guide
|
© National Instruments
|
19
The main blocks of the AO circuitry are as follows:
•
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