Chapter 4
Analog Input
©
National Instruments
4-23
X Series User Manual
Using Non-Referenced Single-Ended (NRSE)
Connections for Ground-Referenced Signal Sources
Fig
u
re 4-11 shows how to connect gro
u
nd-reference signal so
u
rces in
NRSE mode.
Figure 4-11.
Single-Ended Connections for Ground-Referenced Signal Sources
(NRSE Configuration)
AI <0..31> and AI SENSE m
u
st both remain within ±11 V of AI GND.
To meas
u
re a single-ended, gro
u
nd-referenced signal so
u
rce, yo
u
m
u
st
u
se
the NRSE gro
u
nd-reference setting. Connect the signal to one of
AI <0..15> and connect the signal local gro
u
nd reference to AI SENSE.
Yo
u
also can connect the signal to one of AI <16..31> and connect the
signal local gro
u
nd reference to AI SENSE 2. AI SENSE is internally
connected to the negative inp
u
t of the NI-PGIA. Therefore, the gro
u
nd
point of the signal connects to the negative inp
u
t of the NI-PGIA.
Any potential difference between the device gro
u
nd and the signal gro
u
nd
appears as a common-mode signal at both the positive and negative inp
u
ts
of the NI-PGIA, and this difference is rejected by the amplifier. If the inp
u
t
circ
u
itry of a device were referenced to gro
u
nd, as it is in the RSE
gro
u
nd-reference setting, this difference in gro
u
nd potentials wo
u
ld appear
as an error in the meas
u
red voltage.
MIO X
S
erie
s
Device Config
u
red in NR
S
E Mode
Inp
u
t M
u
ltiplexer
s
I/O Connector
AI GND
AI
S
EN
S
E
or AI
S
EN
S
E 2
AI <0..15>
or AI <16..
3
1>
–
+
–
+
V
cm
V
s
Gro
u
nd-
Referenced
S
ign
a
l
S
o
u
rce
Common-
Mode
Noi
s
e
a
nd Gro
u
nd
Potenti
a
l
PGIA
–
+
–
+
V
m
Me
asu
red
Volt
a
ge
In
s
tr
u
ment
a
tion
Amplifier
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