Chapter 4 Analog InputM Series User Manual 4-22 ni.comWhen to Use Non-Referenced Single-Ended (NRSE) Connections withGround-Referenced Signal SourcesOnly use non-referenced single-ended input connections if the input signalmeets 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).• The input signal can share a common reference point with othersignals.DIFF input connections are recommended for greater signal integrity forany input signal that does not meet the preceding conditions.In the single-ended modes, more electrostatic and magnetic noise couplesinto the signal connections than in DIFF configurations. The coupling is theresult of differences in the signal path. Magnetic coupling is proportionalto the area between the two signal conductors. Electrical coupling is afunction of how much the electric field differs between the two conductors.With this type of connection, the NI-PGIA rejects both the common-modenoise in the signal and the ground potential difference between the signalsource and the device ground.Refer to the Using Non-Referenced Single-Ended (NRSE) Connections forGround-Referenced Signal Sources section for more information aboutNRSE connections.When to Use Referenced Single-Ended (RSE) Connections withGround-Referenced Signal SourcesDo not use RSE connections with ground-referenced signal sources. UseNRSE or DIFF connections instead.As shown in the bottom-rightmost cell of Table 4-6, there can be a potentialdifference between AI GND and the ground of the sensor. In RSE mode,this ground loop causes measurement errors.
