Chapter 3 connector and led information, I/o connector signal descriptions, Table 3-1. i/o connector signals – National Instruments Data Acquisition Device NI USB-621x User Manual
Page 29: I/o connector signal descriptions -1, Connector and led information
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3-1
3
Connector and LED Information
The I/O Connector Signal Descriptions and
sections contain
information about NI USB-621x connectors. The
section contains information about the NI USB-621x PWR/ACT LED.
Refer to Appendix A,
, for device I/O
connector pinouts. Refer to the
Applying Signal Labels to the USB-621x
section of Chapter 1,
, for information about applying signal
labels.
I/O Connector Signal Descriptions
Table 3-1 describes the signals found on the I/O connectors. Not all signals
are available on all devices.
Table 3-1. I/O Connector Signals
Signal Name
Reference
Direction
Description
AI GND
—
—
Analog Input Ground—These terminals are the reference
point for single-ended AI measurements in RSE mode and the
bias current return point for DIFF measurements. All three
ground references—AI GND, AO GND, and D GND—are
connected on the device.
AI <0..31>
Varies
Input
Analog Input Channels 0 to 31—For single-ended
measurements, each signal is an analog input voltage channel.
In RSE mode, AI GND is the reference for these signals. In
NRSE mode, the reference for each AI <0..31> signal is
AI SENSE.
For differential measurements, AI 0 and AI 8 are the positive
and negative inputs of differential analog input channel 0.
Similarly, the following signal pairs also form differential input
channels:
AI SENSE
—
Input
Analog Input Sense—In NRSE mode, the reference for each
AI <0..31> signal is AI SENSE.