National Instruments 6023E, 6024E, 6025E Differential Connection Considerations (DIFF Input Configuration)

Chapter4 SignalConnections
©NationalInstruments Corporation 4-13 6023E/6024E/6025EUser Manual
Differential Connection Considerations (DIFF Input Configuration)
A DIFF connection is one in which the analog input signal has its own
reference signal or signal return path. These connections are available
whenthe selectedchannel is configured in DIFF input mode. The input
signal iscon nected tot he positive input of the PGIA, and its reference
signal,or return, is connected to the negative input of the PGIA.
When you configurea channel for DIFF input, each signal uses two
multiplexerinputs—one for the signal and one for its reference signal.
Therefore,with a DIFF configuration for every channel, up to eight analog
inputchannels areavailable.
UseDIFF input connections for any channel that meets any of the following
conditions:
•The input signal is lowlevel (less than 1 V).
•The leads connecting the signal to the deviceare greater than
3m(10ft).
•The input signal requires a separate ground-reference point or return
signal.
•The signal leads travelthrough noisy environments.
DIFFsi gnal connections reduce picked up noise and increase
common-modenoise rejection. DIFFsignal connections also allow input
signals to float within the common-mode limits of the PGIA.