Chapter 4
Analog Input
4-26
ni.com
Differential 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 differential 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 Connections for Floating
section for more information abo
u
t referenced single-ended
connections.
When to Use Non-Referenced Single-Ended
Connections with Floating Signal Sources
Only
u
se non-referenced single-ended 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).
Differential 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 differential 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 Connections for Floating
section for more information abo
u
t non-referenced
single-ended connections.
