Connector And Led Information; I/O Connector Signal Descriptions - National Instruments USB-621 Series User Manual

Connector and LED Information

I/O Connector Signal Descriptions

Signal Name
AI GND
AI <0..31>
AI SENSE
© National Instruments Corporation
The I/O Connector Signal Descriptions and
information about NI USB-621x connectors. The
section contains information about the NI USB-621x PWR/ACT LED.
Refer to Appendix A,
connector pinouts. Refer to the
section of Chapter 1,
labels.
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
Reference Direction
— —
Varies Input
— Input
Device-Specific Information, for device I/O
Applying Signal Labels to the USB-621x
Getting Started, for information about applying signal
Description
Analog Input Ground—These terminals are the reference
point for single-ended AI measurements in RSE mode and the
bias current return point for differential measurements. All three
ground references—AI GND, AO GND, and D GND—are
connected on the device.
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 1, AI 9>, <AI 2, AI 10>, <AI 3, AI 11>, <AI 4, AI 12>,
<AI 5, AI 13>, <AI 6, AI 14>, <AI 7, AI 15>, <AI 16, AI 24>,
<AI 17, AI 25>, <AI 18, AI 26>, <AI 19, AI 27>,
<AI 20, AI 28>, <AI 21, AI 29>, <AI 22, AI 30>,
<AI 23, AI 31>
Analog Input Sense—In NRSE mode, the reference for each
AI <0..31> signal is AI SENSE.
3-1
3
+5 V Power sections contain
PWR/ACT LED Indicator
NI USB-621x User Manual