Chapter 4 Signal Connections©National Instruments Corporation4-17PCI-6023E/6024E/6025E User ManualSingle-Ended Connection ConsiderationsA single-ended connection is one in which the board analog input signal isreferenced to a ground that can be shared with other input signals. The inputsignal is tied to the positive input of the PGIA, and the ground is tied to thenegative input of the PGIA.When every channel is configured for single-ended input, up to 16 analoginput channels are available.You can use single-ended input connections for any input signal that meetsthe following conditions:• The input signal is high level (greater than 1 V).• The leads connecting the signal to the board are less than 10 ft (3 m).• 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.Using your software, you can configure the channels for two different typesof single-ended connections—RSE configuration and NRSE configuration.The RSE configuration is used for floating signal sources; in this case, theboard provides the reference ground point for the external signal. TheNRSE input configuration is used for ground-referenced signal sources; inthis case, the external signal supplies its own reference ground point and theboard should not supply one.In single-ended configurations, more electrostatic and magnetic noisecouples into the signal connections than in differential configurations. Thecoupling is the result of differences in the signal path. Magnetic couplingis proportional to the area between the two signal conductors. Electricalcoupling is a function of how much the electric field differs between thetwo conductors.
