Chapter 4
Analog Input
4-26
ni.com
DIFF inp
u
t connections are recommended for greater signal integrity for
any inp
u
t signal that does not meet the preceding conditions.
In the single-ended modes, more electrostatic and magnetic noise co
u
ples
into the signal connections than in DIFF config
u
rations. 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.
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.
Refer to the
Using Referenced Single-Ended (RSE) Connections for
section for more information abo
u
t RSE
connections.
When to Use Non-Referenced Single-Ended (NRSE)
Connections with Floating Signal Sources
Only
u
se NRSE inp
u
t connections if the inp
u
t signal meets the following
conditions:
•
The inp
u
t signal is high-level (greater than 1 V).
•
The leads connecting the signal to the device are less than 3 m (10 ft).
DIFF inp
u
t connections are recommended for greater signal integrity for
any inp
u
t signal that does not meet the preceding conditions.
In the single-ended modes, more electrostatic and magnetic noise co
u
ples
into the signal connections than in DIFF config
u
rations. 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.
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.
Refer to the
Using Non-Referenced Single-Ended (NRSE) Connections for
section for more information abo
u
t NRSE
connections.
