[volt-nuts] correlate volt meters for more accurate readings

[Jerry Hancock]

Hello all,

I’ve been running plots of my various and rebuilt volt standards (aka DAS-46 which we have working now) and during that process, someone mentioned to me about using two meters at once and then correlating the outputs.  I have a pair of both 3457a’s and 3456a’s,  and though the 3457a has the extra digit, the 3456a meters seem to be more stable.

So assuming I get a time-stamped dataset from both meters, for instance the 3457A meters in hi-res mode, would I just average the two samples?  And if so, would that add a significant level of accuracy for me to change the code, which will only take about 10 minutes maybe?  I guess it could remove some noise, no?  I could actually run the two from two visual basic programs, triggered by a software pipe, so instead of reading the meters from one program sequentially, I can trigger both programs from a 3rd program using a pipe.  

What do you think?  I’ll probably play around with it today, but was wondering if there was higher math needed than just say averaging the data sets by point.  In NPLC=100 mode, the 3457A read loop is a little less than 4 seconds using visual basic.  I generally grab about 7,000 to 10,000 data points.

Thanks.