I thought this was going to be a straightforward problem, and here I am, a few hours later no further ahead. I have a two columns in very large table. One is a time in format hh:mm. The other is a series of measurements. All the measurements are taken over a 24 hour period (or slightly less) and the time recorded as hh:mm. What I really need is an elapsed time from the first measurement. The problem is that everything is referenced to 00:00 and so the calculations go all whacky at that point as it doesn't know it is the next day and the data set is far too big for me to add the day manually. Any and all thoughts are gratefully appreciated!
The other weird thing I found was that the data file behaved quite differently depending upon whether I imported the Excel file, or save the Excel file as a .txt file and imported it. The latter was much better.
