With floating signal sources -4 – National Instruments NI USB-621x User Manual
Page 54
Chapter 5
Connecting AI Signals on the USB-6210/6211 Devices
5-4
ni.com
In the single-ended modes, more electrostatic and magnetic noise couples
into the signal connections than in DIFF configurations. The coupling is the
result of differences in the signal path. Magnetic coupling is proportional
to the area between the two signal conductors. Electrical coupling is a
function of how much the electric field differs between the two conductors.
With this type of connection, the NI-PGIA rejects both the common-mode
noise in the signal and the ground potential difference between the signal
source and the device ground.
Refer to the
Using Referenced Single-Ended (RSE) Connections for
section for more information about RSE
connections.
When to Use Non-Referenced Single-Ended (NRSE) Connections with
Floating Signal Sources
Only use NRSE input connections if the input signal meets the following
conditions.
•
The input signal is high-level (greater than 1 V).
•
The leads connecting the signal to the device are less than 3 m (10 ft).
DIFF input connections are recommended for greater signal integrity for
any input signal that does not meet the preceding conditions.
In the single-ended modes, more electrostatic and magnetic noise couples
into the signal connections than in DIFF configurations. The coupling is the
result of differences in the signal path. Magnetic coupling is proportional
to the area between the two signal conductors. Electrical coupling is a
function of how much the electric field differs between the two conductors.
With this type of connection, the NI-PGIA rejects both the common-mode
noise in the signal and the ground potential difference between the signal
source and the device ground.
Refer to the
Using Non-Referenced Single-Ended (NRSE) Connections for
section for more information about NRSE
connections.