When To Use Referenced Single-Ended (Rse) Connections With Ground-Referenced Signal Sources; Using Differential Connections For Ground-Referenced Signal Sources - National Instruments X Series User Manual

When to Use Referenced Single-Ended (RSE) Connections with
Ground-Referenced Signal Sources
Do not use RSE connections with ground-referenced signal sources. Use NRSE or DIFF
connections instead.
As shown in the bottom-rightmost cell of Table 4-3, there can be a potential difference between
AI GND and the ground of the sensor. In RSE mode, this ground loop causes measurement
errors.
Using Differential Connections for Ground-Referenced Signal
Sources
Figure 4-10 shows how to connect a ground-referenced signal source to the MIO X Series device
configured in differential mode.
Figure 4-10. Differential Connections for Ground-Referenced Signal Sources
Ground-
Referenced
Signal
Source
Common-
Mode
Noise and
Ground
Potential
I/O Connector
Note (NI USB-6341/6343/6346/6361/6363 BNC Devices)
ground-referenced signal source on X Series USB BNC devices, move the switch
under the BNC connector to the GS position.
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 Vcm
in the figure.
AI+ and AI- must both remain within ±11 V of AI GND.
+
V
s
–
+
V
cm
–
Input Multiplexers
AI SENSE
AI GND
MIO X Series Device Configured in Differential Mode
AI+
Instrumentation
+
PGIA
AI–
–
X Series User Manual
Amplifier
+
Measured
V
m
Voltage
–
To measure a
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