National Instruments USB-6210 - Connecting Ground-Referenced Signal Sources

Chapter 4 Analog Input
© National Instruments Corporation 4-31 NI USB-621x User Manual
Using the DAQ Assistant, you can configure the channels for referenced
single-ended or non-referenced single-ended input modes. Refer to the
Configuring AI Ground-Reference Settings in Software section for more
information about the DAQ Assistant.
Using Referenced Single-Ended Connections for
Floating Signal Sources
Figure 4-21 shows how to connect a floating signal source to the
USB-6210/6211/6212 device configured for referenced single-ended
mode.
Figure 4-21. Referenced Single-Ended Connections for Floating Signal Sources
Using the DAQ Assistant, you can configure the channels for referenced
single-ended or non-referenced single-ended input modes. Refer to the
Configuring AI Ground-Reference Settings in Software section for more
information about the DAQ Assistant.
Connecting Ground-Referenced Signal Sources
What Are Ground-Referenced Signal Sources?
A ground-referenced signal source is a signal source connected to the
building system ground. It is already connected to a common ground point
with respect to the device, assuming that the computer is plugged into the
same power system as the source. Non-isolated outputs of instruments and
devices that plug into the building power system fall into this category.
Selected Channel in RSE Configuration
PGIA
Input Multiplexers
–
+
–
Floating
Signal
Source
V
s
I/O Connector
AI GND
AI SENSE
AI <0..n>
+
Programmable Gain
Instrumentation
Amplifier
Measured
Voltage
V
m
–
+