Chapter 2
Hardware Overview of the NI 78xxR
©
National Instruments Corporation
2-11
R Series Multifunction RIO User Manual
Differential Connections for Ground-Referenced
Signal Sources
Fig
u
re 2-6 shows how to connect a gro
u
nd-referenced signal so
u
rce to a
channel on the NI 783
x
R/784
x
R/785
x
R config
u
red in DIFF inp
u
t mode.
Figure 2-6.
Differential Input Connections for Ground-Referenced Signals
With this connection type, the instr
u
mentation amplifier rejects both the
common-mode noise in the signal and the gro
u
nd potential difference
between the signal so
u
rce and the NI 783
x
R/784
x
R/785
x
R gro
u
nd, shown
as V
cm
in Fig
u
re 2-6. In addition, the instr
u
mentation amplifier can reject
common-mode noise pick
u
p in the leads connecting the signal so
u
rces to
the device. The instr
u
mentation amplifier can reject common-mode signals
when V+
in
and V–
in
(inp
u
t signals) are both within their specified inp
u
t
ranges. Refer to the
NI R Series Multifunction RIO Specifications
, available
at
ni.com/manual
s
, for more information abo
u
t inp
u
t ranges.
DIFF Input Mode Selected
–
+
–
+
–
+
–
+
V
cm
V
s
I/O Connector
AISENSE
AIGND
V
m
AI+
AI–
Ground-
Referenced
Signal
Source
Common-
Mode
Noise and
Ground
Potential
Measured
Voltage
Instrumentation
Amplifier
Summary of Contents for Multifunction RIO NI R Series
Page 1: ...PXI 7813...
