National Instruments SCB-68 - Manual (Page 29)

© National Instruments Corporation 3-1 SCB-68 Shielded Connector Block User Manual
3
Connecting Signals
This chapter describes the types of signal sources that you use when
configuring the channels and making signal connections to the SCB-68,
describes input modes, and discusses noise considerations to help you
acquire accurate signals.
Connecting Analog Input Signals
The following sections describe how to connect signal sources for
single-ended or differential (DIFF) input mode. On most devices, you can
software-configure the DAQ device channels for two types of single-ended
connections—nonreferenced single-ended (NRSE) input mode and
referenced single-ended (RSE) mode. RSE input mode is used for floating
signal sources. In this case, the DAQ device provides the reference
ground point for the external signal. NRSE input mode is used for
ground-referenced signal sources. In this case, the external signal supplies
its own reference ground point, and the DAQ device should not supply one.
Note Some devices might only support one of the possible input modes.
Input Modes
You can configure the DAQ device for one of three input modes—NRSE,
RSE, or DIFF. The following sections discuss the use of single-ended and
differential measurements and considerations for measuring both floating
and ground-referenced signal sources. On devices that support both
single-ended and DIFF input modes, using DIFF input mode commits two
channels, ACH<i> and ACH<i+8>, to each signal. Figure 3-1 summarizes
the recommended input modes for both types of signal sources.