Chapter 4
Analog Input
4-34
ni.com
Using Differential Connections for
Ground-Referenced Signal Sources
Fig
u
re 4-22 shows how to connect a gro
u
nd-referenced signal so
u
rce to the
USB-6210/6211/6212 device config
u
red in differential mode.
Figure 4-22.
Differential Connections for Ground-Referenced Signal Sources
With this type of connection, the NI-PGIA rejects both the common-mode
noise in the signal and the gro
u
nd potential difference between the signal
so
u
rce and the device gro
u
nd, shown as V
cm
in the fig
u
re.
AI+ and AI– m
u
st both remain within ±11 V of AI GND.
U
S
B-6210/6211/6212 Config
u
red in DIFF Mode
PGIA
–
+
–
+
–
+
–
+
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
AI GND
AI
S
EN
S
E
Inp
u
t M
u
ltiplexer
s
V
m
Me
asu
red
Volt
a
ge
In
s
tr
u
ment
a
tion
Amplifier
AI
+
AI
–
I/O Connector
