Why do the RSE & NRSE modes seemed to be reversed?

[LoKey]

Why do the RSE and NRSE modes of analog input configuration seem to be reversed. LV7.0, NI-DAQ7.0 MAX3.0, PCI-MIO-16E-1.
RSE mode with a floating signal lets it drift to the rail whereas, NRSE with a floating signal seems to produce a stable normal measurement.
It seems that it is the NRSE mode that provides a ground reference. This is NOT as described in all manuals.

[RIO-Todd]

Hello Paul,

RSE will be the configuration mode that will be referenced to the ground of the device (AIGND). NRSE will be referenced to the AISENSE pin of the device which is floating. Make sure you are connecting the negative terminal of your input to AIGND for RSE and AISENSE for NRSE.

Are you seeing this in Measurement and Automation Explorer (MAX) or in LabVIEW (or both)?

--By default, the configuration of the device will be differential. If you change the configuration to RSE in MAX and then go into LabVIEW and run an example DAQ program, the device will actually be configured in differential mode. This is because there is an input to the AI Config VI that by default sets the configuration of the DAQ device back to differential and will override t
he MAX configuration.

To configure the device for RSE in LabVIEW, you can use the 'coupling & input config' input of the AI Config VI. You will need to change the configuration mode to be referenced single ended within this input cluster. After configuring the device for RSE mode, you will then be able to connect the positive terminal of the signal to channel X and the negative terminal of the signal to AIGND.

I hope this helps. Let me know if you have any additional questions.

Regards,

Todd D.
NI Applications Engineer