National Instruments Data Acquisition Device NI USB-621x User Manual

Page 71

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Chapter 4

Analog Input

NI USB-621x User Manual

4-38

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Taking 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 instrumentation
amplifier (PGIA) that is shared among all channels configured for NRSE
mode. The behavior of this configuration is similar to that of RSE
connections, except it provides improved noise rejection. Figure 4-26
shows an NRSE connection configuration.

Figure 4-26. Connecting to the USB-6215/6216/6218 in NRSE Mode

In NRSE connection configuration, each input channel is measured with
respect to AI SENSE.

AI 1

AI 0

AI GND

Mux

ADC

PGIA

AI SENSE

USB-6215/6216/6218

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