Data Acquisition Idea Exchange

[#1]

I'm not sure who reads this, but I'm not seeing any feedback in the forum so I thought I'd post up here.   This may seem like a simple thing, but hopefully my pain will be someone else gain.  I messed with this off and on for two months before I finally figured it out.  It's probably obvious to those who work with this equipment every day and have EE degrees, but not so much to those of us who do not. 

Please see http://forums.ni.com/t5/Multifunction-DAQ/Measuring-220VAC-with-CompactDAQ/td-p/1145956 for a description of the issues I was having. 

Some will tell me to "search"... well, I did.  ...and everywhere I looked all I found was that I needed to measure from the power leg to ground.  All of the examples either were only measuring 120 which is fine since what you have is one power leg and neutral... which is basically ground!  So those numbers come out fine.  Or they were for 3 phase, which I don't use currently.  BUT when you try and measure anything with two power legs (basically anything between 208VAC to 240 VAC) the numbers don't work out right if you try to measure between each power leg to ground and then try to recombine them and plug them into the Power VI's.  Not one place that I looked did it tell me that I need to measure both power legs across a single channel.  I only finally tried it because I'd done pretty much everything else.  I know this is pretty basic stuff, but when all you give me says one thing... that's what we do.  Just trying to help others.

Thanks,

Chad