National Instruments NI USB-621x - Manual (Page 67)

Chapter 6 Connecting AI Signals on the USB-6215/6218 Devices
NI USB-621x User Manual 6-4 ni.com
Non-Referenced Single-Ended (NRSE) Measurements
To reach a compromise between RSE and differential measurements, you
can use an NRSE measurement configuration. This configuration allows
for a remote sense for the negative (–) input of the programmable gain
instrumentation amplifier (PGIA) that is shared among all channels
configured for NRSE mode. The behavior of this configuration is similar to
the behavior of RSE connections but it provides improved noise rejection.
Refer to Figure 6-3 for an illustration of an NRSE connection
configuration.
Figure 6-3. Connecting a Device to a USB-6215/6218 Using NRSE Connections
In the NRSE connection configuration, each input channel is measured
with respect to AI SENSE.
AI1
AI0
AI GND
MUX ADC PGIA
AISENSE
USB-6215/6218