NI USB DAQs - does it have external reference signal?

[prashanthg]

I am trying to read a signal using NI USB 6251 in RSE mode. Is there a reference signal that goes internally for the measurement? If so, is there a way to provide an external signal and measure in RSE mode? (might be a silly question, am a beginner :))

[Bob_Schor]

Not sure if this answers your question, but Terminal 13 should be Analog Sense ...