Reading mV from Current Transformer connected to NI 9206 through cRio Chassis

[Mr.F · Accepted solution]

Yes, sorry, I see now that you had already specified that. The -.15V to .15V oscillations, are they at 60 Hz? Can you oversample that signal and see a sign wave? The voltage and current through the AC power lines of a device will be periodic; my suspicion is that the Fluke DMM is giving you an averaged value or an RMS value. Can you verify with a fast sampling device like an O-scope? The Field Wiring and Noise Considerations for Analog Signals, where I assume you saw to use the bias resistors, correct me if I’m wrong, isn’t directly applicable for isolated cards. Can you connect com to the negative line of the signal and remove the resistors?

[phdieum]

Hey Matt,

I removed the resistors and connected the neg(-) to com.  I then took a RMS of the signal and BINGO!....I got the 0.090v that the Fluke is reading. Thanks a lot for your help. 

-jason