Scatter graphing issue

I am currently having an issue with scatter graph that just has me at wits end. I set up a simple worksheet with multiple places for my employees to take machine readings and enter them. I used a basic NOW() function to timestamp each column anytime they make an entry. I did this for around 30 machines that i am currently tracking. I now have enough data that I want to plot all of them on the same graph with Time being my x-axis. But I plan to continue to use this worksheet for a few more weeks and if I select the entire column for my x-axis it doesn't plot correctly. I had thought that since the values in that column were blank "", that I could have Excel ignore them and treat them as gaps, but that doesn't seem to work. In fact the graph starts my date on saturday and the point directly above is a wednesday! None of the points correspond with the appropriate x values below. I have tried starting the x-axis at a fixed date but then the graph fails to plots any points at all. I believe the problem may lie with the fact that the cells are not in fact "empty" as my timestamp function is there.

=IF(B1="","",IF(A1="",NOW(),A1)) with iterations set to 1.

Now, I could easily just select the data I want and plot it. That would solve my immediate problems. But in about 3 weeks, I will have to go back and reselect all of the data again for each of 30 machines to finalize the data. And I hope to make this an ongoing process. If so I would like to make a monthly template of this worksheet.

I basically need Excel to ignore those "blank" cells until the dates are timestamped into them. It may be that I just need a more sofisticated timestamping function.

doe it help if you replace the double quotes with na() in your formula - usually these are ignored on scatter charts

Unfortunately, no. That's what I meant by the more sofisticated timestamp comment. As soon as the function returns the N/A value, with iterations set to 1 it will never return the second value.

Basically, by researching some more I have found that excel is just converting all those blanks into zeros and plotting them. I just don't understand why. I have gone into and selected to have it use gaps.

Ah, this confirms what I was afraid of then. I will have to take the long way around for now. My contingency plan for this is to start building something in access/VB that can basically do the same thing. It was just simpler to do it in excel until now.

Thanks for the help!