Chapter 4
Analog Input
©
National Instruments Corporation
4-31
Using the DAQ Assistant, yo
u
can config
u
re the channels for RSE or NRSE
inp
u
t modes. Refer to the
Configuring AI Ground-Reference Settings in
section for more information abo
u
t the DAQ Assistant.
Using Referenced Single-Ended (RSE) Connections
for Floating Signal Sources
Fig
u
re 4-21 shows how to connect a floating signal so
u
rce to the
USB-6210/6211/6212 device config
u
red for RSE mode.
Figure 4-21.
RSE Connections for Floating Signal Sources
Using the DAQ Assistant, yo
u
can config
u
re the channels for RSE or NRSE
inp
u
t modes. Refer to the
Configuring AI Ground-Reference Settings in
section for more information abo
u
t the DAQ Assistant.
Connecting Ground-Referenced Signal Sources
What Are Ground-Referenced Signal Sources?
A gro
u
nd-referenced signal so
u
rce is a signal so
u
rce connected to the
b
u
ilding system gro
u
nd. It is already connected to a common gro
u
nd point
with respect to the device, ass
u
ming that the comp
u
ter is pl
u
gged into the
same power system as the so
u
rce. Non-isolated o
u
tp
u
ts of instr
u
ments and
devices that pl
u
g into the b
u
ilding power system fall into this category.
The difference in gro
u
nd potential between two instr
u
ments connected to
the same b
u
ilding power system is typically between 1 and 100 mV, b
u
t the
difference can be m
u
ch higher if power distrib
u
tion circ
u
its are improperly
connected. If a gro
u
nded signal so
u
rce is incorrectly meas
u
red, this
S
elected Ch
a
nnel in R
S
E Config
u
r
a
tion
PGIA
Inp
u
t M
u
ltiplexer
s
–
+
–
Flo
a
ting
S
ign
a
l
S
o
u
rce
V
s
I/O Connector
AI GND
AI
S
EN
S
E
AI <0..
n
>
+
Progr
a
mm
ab
le G
a
in
In
s
tr
u
ment
a
tion
Amplifier
Me
asu
red
Volt
a
ge
V
m
–
+
