National Instruments AT E Series Common-Mode Signal Rejection Considerations

Chapter4 ConnectingSignals

ATE Series User Manual 4-26 ni.com

Figure 4-9 showshow to connect a grounded signal source to an

ATE Series device channel configured for NRSE mode.

Figure4-9. Single-EndedInput Connections for Ground-Referenced Signal

Common-Mode Signal Rejection Considerations

Figures 4-6 and 4-9 show connections for signal sources that are already

referenced to some ground point with respect to the AT E Series device.

In thesecases, the PGIA can reject any voltage caused by ground potential

differencesbetween the signal source and the device. In addition, with

differentialinput c onnections,the PGIA canreject common-mode noise

pickup in the leads connecting the signal sources to the device. The PGIA

can reject common-mode signals as long as Vin+ and Vin–are both within

±11 V of AIGND. The AT-MIO-16XE-50 has the additional restriction

SelectedChannel in NRSE Configuration

PGIA

Programmable

Gain

Instrumentation

Amplifier

–

InputMultiplexers

AISENSE

AIGND

Vcm

–

ACH+

ACH–

Common-

Mode

Noiseand

Ground

Potential

Ground-

Referenced

Signal

Source

Measured

Voltage

I/OConnector