x y data into bins

[erfigge]

Ok, so I'm not for sure exactly how to describe the dilemma I'm trying to solve.  I use a sbRio card to take data for long periods of time.  With the data that is collected I can develop an x y plot.  The x axis has units of flow, the y axis is pressure ratio (unitless).  

I take 5 minute averages of the data collected and do calculations to come up with the above graph.  Now, what I need to do look at that over time and see how it shifts.  The flow rate and PR are related and the data is typically (at least it should be) a fairly linear line.  My first thought was some sort of FFT to place the data into "bins" of flow and see how the associated PR's have changed over time, but I'm not for sure how to implement that or if that was indeed the correct thing to do.  

I came across this post: http://forums.ni.com/t5/LabVIEW/Calculating-averages-of-data-bins/m-p/1066908/highlight/true#M473067

It looks like he was wanting to do the same thing, but not quite.

In case I didn't do a good job of explain it above here is slightly detailed explanation.  Let’s say the mass flow on the x axis is 1, 2, 3 and 4.  And the PR on the y axis is 1 at x=1, 2 at x=2 etc.  What I want to be able to see is if 2 years from now for x=1 if the PR is still about 1, or if it has changed and by how much.  

My sbRio takes the data and sends it to an SQL database.  I use labview to pull the calculated data from the db and display it on charts but haven't been able to display the data.  I even tried the 3D color charts but that really didn't give the effect I was after.

Thanks,

Eric. 

[JÞB]

it sounds like you might want a "Histogram"

Look on the "Mathmatics>>Probability and statistics" sub-palette

[erfigge]

Well, if I understand a histogram, what that shows is the number of times a particular data point or in this case PR value is corresponding to a particular mass flow.  This doesn't really show me anything over time.  Unless I'm not understanding.....