Chapter 2
Hardware Overview of the NI 78xxR
R Series Multifunction RIO User Manual
2-14
ni.com
Use DIFF inp
u
t connections for greater signal integrity for any inp
u
t signal
that does not meet the preceding conditions.
Yo
u
can config
u
re the NI 783
x
R/784
x
R/785
x
R channels in software for
RSE or NRSE inp
u
t modes. Use the RSE inp
u
t mode for floating signal
so
u
rces. In this case, the NI 783
x
R/784
x
R/785
x
R provides the reference
gro
u
nd point for the external signal. Use the NRSE inp
u
t mode for
gro
u
nd-referenced signal so
u
rces. In this case, the external signal s
u
pplies
its own reference gro
u
nd point and the NI 783
x
R/784
x
R/785
x
R sho
u
ld not
s
u
pply one.
In single-ended inp
u
t modes, electrostatic and magnetic noise co
u
ples into
the signal connections more than in differential inp
u
t modes. The co
u
pling
is the res
u
lt of differences in the signal path. Magnetic co
u
pling
is proportional to the area between the two signal cond
u
ctors. Electrical
co
u
pling is a f
u
nction of how m
u
ch the electric field differs between the
two cond
u
ctors.
Single-Ended Connections for Floating Signal
Sources (RSE Input Mode)
Fig
u
re 2-8 shows how to connect a floating signal so
u
rce to a channel on
the NI 783
x
R/784
x
R/785
x
R config
u
red for RSE inp
u
t mode.
Figure 2-8.
Single-Ended Input Connections for Nonreferenced or Floating Signals
–
+
–
+
–
+
I/O Connector
AISENSE
AIGND
V
m
AI+
AI–
V
s
Floating
Signal
Source
Instrumentation
Amplifier
Measured
Voltage
RSE Input Mode Selected
Содержание NI 783 R Series
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