cRIO-9215 problem

[Jeremy@Thermadyne]

I am using a cRIO-9215 with a clamp on current probe.  The probe outputs 1mv/A (Maximum of 1.5V/1500A).  I typically am measuring currents from 200-1000A but I am unable to get consistent data.  I am receiving data using the DAQmx assistant in LabVIEW to receive data (once per second).  If I am measuring a current that is 500A then LabVIEW will fluctuate anywhere between 450A-550A even though the current is actually very close to a constant 500A.  I'm pretty sure that my current probe is functioning correctly because when I measure the output with a Fluke multi-meter I am receiving the correct voltage with no fluctuations.  What am I doing wrong? 

Thanks in advance.

[McKala[DE]]

Hello BIllBraskey,

For my information, are you using a Compact DAQ chassis or are you using the Compact RIO chassis?  There are a couple possible reasons why you are seeing such fluctuation in your measurements.  If you are in a very noisy environment it may be getting picked up in your measurement.  The second is that you may have improperly connected the ground for your system.  What type of input configuration are you using (differential, single-ended ground references, etc)?  A good starting point to troubleshoot either one of these problems is the Field Wiring and Noise Considerations for Analog Signals tutorial. 

Post again if you don't see improvement and we'll help you more from there.