I am using two particle counters that are filling columns A and B for 2000 data points. Column C is doing a mathmatical computational result to column A. To get Column C to compute what happens in A as it progresses I have to copy the function in C1 Into C2-C2000.

On column A and B, I can use the =index(a:a,counta(A:A),1) To return the last value added so my graphical display shows the user only the last posted value. If I use the same formula on C:C the data only posts when the A and B reach A2000 and B2000; therefore, as the chart progresses there is no way to display A1,B1,C1 current data values. I can only post A2000,B2000,C2000 where the copy paste of Column C ends.

What I need is to have some way that when column A and B post a live value, a similar live value is posted in D that is the result from Column C that is only popluated when A and B are posted.

Posting in cell D# (=C#) and copying for 2000 cells does not work as Counta sees the blank cells even when they are empty as results and will not allow the last value to be returned until reaching cell 2000. I wish I could make a Column E and do something like this =if(a#>0, C#=D#, C#=F#). I know this is not possible, but it would have the effect of posting a non equation value of C into D only when a value is posted into A by a particle counter. This would allow counta to see the last value posted in D and it would be in sync with column A.

If I have not confussed the heck out you, any suggestions would help.