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National Instruments Corporation
11
NI USB-6008/6009 User Guide and Specifications
Signal Descriptions
Table 5 describes the signals available on the I/O connectors.
Table 5.
Signal Descriptions
Signal Name
Reference
Direction
Description
GND
—
—
Ground
—The reference point for the
single-ended AI measurements, bias
current return point for differential mode
measurements, AO voltages, digital
signals at the I/O connector,
+
5 VDC
supply, and the
+
2.5 VDC reference.
AI <0..7>
Varies
Input
Analog Input Channels 0 to 7
—For
single-ended measurements, each signal is
an analog input voltage channel. For
differential measurements, AI 0 and AI 4
are the positive and negative inputs of
differential analog input channel 0.
The following signal pairs also form
differential input channels:
<AI 1, AI 5>, <AI 2, AI 6>, and
<AI 3, AI 7>.
AO 0
GND
Output
Analog Channel 0 Output
—Supplies the
voltage output of AO channel 0.
AO 1
GND
Output
Analog Channel 1 Output
—Supplies the
voltage output of AO channel 1.
P1.<0..3>
P0.<0..7>
GND
Input or
Output
Digital I/O Signals
—You can
individually configure each signal as an
input or output.
+
2.5 V
GND
Output
+
2.5 V External Reference
—Provides a
reference for wrap-back testing.
+
5 V
GND
Output
+
5 V Power Source
—Provides
+
5 V
power up to 200 mA.
PFI 0
GND
Input
PFI 0
—This pin is configurable as either a
digital trigger or an event counter input.
