Chapter 5 Connecting AI Signals on the USB-6210/6211 Devices© National Instruments Corporation 5-9 NI USB-621x User Manualconnection is shared with all channels rather than being cabled in a twistedpair with the AI+ signal.Using the DAQ Assistant, you can configure the channels for RSE or NRSEinput modes. Refer to the Configuring AI Ground-Reference Settings inSoftware section of Chapter 4, Analog Input, for more information aboutthe DAQ Assistant.Using Referenced Single-Ended (RSE) Connections for Floating SignalSourcesFigure 5-6 shows how to connect a floating signal source to the NI 621xdevice configured for RSE mode.Figure 5-6. RSE Connections for Floating Signal SourcesUsing the DAQ Assistant, you can configure the channels for RSE or NRSEinput modes. Refer to the Configuring AI Ground-Reference Settings inSoftware section of Chapter 4, Analog Input, for more information aboutthe DAQ Assistant.Connecting Ground-Referenced Signal SourcesWhat Are Ground-Referenced Signal Sources?A ground-referenced signal source is a signal source connected to thebuilding system ground. It is already connected to a common ground pointwith respect to the device, assuming that the computer is plugged into thesame power system as the source. Non-isolated outputs of instruments anddevices that plug into the building power system fall into this category.Selected Channel in RSE ConfigurationPGIAInput Multiplexers–+–FloatingSignalSourceVsI/O ConnectorAI GNDAI SENSEAI <0..n>+Programmable GainInstrumentationAmplifierMeasuredVoltageV m–+
