National Instruments DAQ X Series User Manual

Chapter 4 Analog Input
X Series User Manual 4-48 ni.com
Differential Connections for Ground-Referenced
Signal Sources
Figure 4-26 shows how to connect a ground-referenced signal source to a
channel on an Simultaneous MIO X Series device.
Figure 4-26. Differential Connection for Ground-Referenced Signals on Simultaneous
MIO X Series Devices
With these types of connections, the instrumentation amplifier 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
cm
in
Figure 4-26.
Common-Mode Signal Rejection Considerations
The instrumentation amplifier can reject any voltage caused by ground
potential differences between the signal source and the device. In addition,
the instrumentation amplifier can reject common-mode noise pickup in the
leads connecting the signal sources to the device. The instrumentation
amplifier can reject common-mode signals as long as V+
in
and V–
in
(input
signals) are both within the working voltage range of the device.
Ground-
Referenced
Signal
Source
Common-
Mode Noise
and Ground
Potential
V
s
V
cm
+
–
+
–
I/O Connector
AI 0 Connections Shown
AI 0 GND
AI 0 –
AI 0 +
+
–
+
–
V
m
Measured
Voltage
Instrumentation
Amplifier
Simultaneous X Series Device
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com

National Instruments DAQ X Series Specifications

General

Brand	National Instruments
Model	DAQ X Series
Category	I/O Systems
Language	English