Using Non-Referenced Single-Ended (Nrse) Connections For Ground-Referenced Signal Sources - National Instruments Data Acquisition Device NI USB-621x User Manual

Chapter 4 Analog Input
NI USB-621x User Manual
Ground-
+
Referenced
V
Signal
s
–
Source
Common-
+
Mode
V
cm
Noise and
–
Ground
Potential
I/O Connector
Figure 4-22. Differential Connections for Ground-Referenced Signal Sources
With this type of connection, the NI-PGIA rejects both the common-mode
noise in the signal and the ground potential difference between the signal
source and the device ground, shown as V
AI+ and AI– must both remain within ±11 V of AI GND.
Using Non-Referenced Single-Ended (NRSE)
Connections for Ground-Referenced Signal Sources
Figure 4-23 shows how to connect ground-reference signal sources to the
USB-6210/6211/6212 device in NRSE mode.
AI +
AI –
Input Multiplexers
AI SENSE
AI GND
USB-6210/6211/6212 Configured in DIFF Mode
cm
4-34
Instrumentation
Amplifier
+
+
PGIA
Measured
–
V
m
Voltage
–
in the figure.
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