ref Single ended signals

[Clint1000]

I have a test set connected to a PXI-6229 via a SCB68 in a drawer in the test cabinet.  In my code I use RSE to measure the various inputs to my DAQ.  I have 4 ( 24 VDC,15 VDC, 12 VDC and a 5 VDC) power supplies that send power out to the test set to run different things.  Back in my drawer I connect my analog in ground ( SCB68) , my digital ground ( scb68)  the power supplies minus and the safety ground from the 120 vac to a single point ground in the drawer.  I did not use NRSE w a resistor to ground anywhere.  Is this..legit??  Everything seems to be working in the Lab but things could chg when the test set gets out in the field.  All my measurements are DC and less than 15 VDC.  I've included a crude drawing.if it helps.

I asked because I REALLY misunderstood the nomenclature of RSE, NRSE and Differential.  I thought RSE was ref single ended meaning one end of the measurement was grounded.  Differential was floating like in a handheld DMM measuring a battery.  No grounding involved..and NRSE...never even considered this one..

[Duffy2007 · Accepted solution]

Hello Clint1000,

if all GND are connected to the same Earth ground RSE is the right measurement.

Field Wiring and Noise Considerations for Analog Signals

NRSE is a good choise, if you have a small difference between the GND of the DAQ device and the Earth ground to compensate.

Differential measurements help to compensate the influence, which can be introduced by the wires, because the influence happened on both wires.

[Clint1000]

thxs..