National Instruments NI PXI-7831R - Manual (Page 33)

Chapter 2 Hardware Overview of the NI PXI-7831R
NI PXI-7831R User Manual 2-12 ni.com
the NI PXI-7831R provides the reference ground point for the external
signal. The NRSE input mode is used for ground-referenced signal sources;
in this case, the external signal supplies its own reference ground point and
the NI PXI-7831R should not supply one.
In single-ended input modes, more electrostatic and magnetic noise couples
into the signal connections than in differential input modes. The coupling
is the result of differences in the signal path. Magnetic coupling
is proportional to the area between the two signal conductors. Electrical
coupling is a function of how much the electric field differs between the
two conductors.
Single-Ended Connections for Floating Signal
Sources (RSE Input Mode)
Figure 2-7 shows how to connect a floating signal source to a channel on
the NI PXI-7831R configured for RSE input mode.
Figure 2-7. Single-Ended Input Connections for Nonreferenced or Floating Signals
Single-Ended Connections for Grounded Signal
Sources (NRSE Input Mode)
To measure a grounded signal source with a single-ended input mode, you
must configure the NI PXI-7831R in the NRSE input mode. The signal is
then connected to the positive input of the NI PXI-7831R instrumentation
RSE Input Mode Selected
–
+
–
+
–
+
Floating
Signal
Source
I/O Connector
AISENSE
AIGND
V
m
Measured
Voltage
Instrumentation
Amplifier
x8 Channels
AI+
AI–
V
s