Time vs. Temp - total positive slope

[Grover]

I accumulate data for time vs. temperature, and would like to sum the times that the temperature is increasing - that is, if the temp in the next cell is greater than the current cell, show the time interval. Then at the end of a selected period, say when the date changes, sum the number of minutes that the temperature interval increased. I'm not sure of the correct formula to use.

The spreadsheet I have consists of 3 columns: date, time (minutes), and temperature - can attach a sample if this is not clear.

Thank you in advance.

Grov

[oldchippy]

Hello there,

If you want to provide a small zipped sample of your worksheet with exactly what you want then we can have a look for you.

To post a zipped example, go to “My Documents” or wherever you have your file stored, right-click and “Send to > Compressed file”, then attach this zipped file to your post.

[Grover]

Here's an example for the first hour of the first day of January.

I constructed this manually to illustrate the desired function from the real data.
I may have to change the sample interval to get the desired resolution of the final data - right now it's set for a 2 minute sample, may have to go to 1 minute or even 30 seconds....

Thanks again for help.

Grov

[oldchippy]

Does this work for you, in cell D1

=IF(C3>C2,B3-B2,"") copy down

[Grover]

Your formula worked like a charm; I, being rusty (worked a lot with Excel 10-15 years ago), was overcomplicating things....

Now, how to consolidate the data.....

I want to get a sum of column D, when the date changes.... I've manually gone into the sheet, inserted a blank row, and used the sum function to capture all the times in column D - works great. But, how to automate (seems like I remember a function that would act when a value, like date, changed). Anyway, doing a sort on column D, because the formulas all relate to a previous cell, I get garbage; that is, I cannot get a sort to show me the total for a group of dates......

Many thanks from this rusty old buzzard!

Grov

[oldchippy]

Hi Grov,

Try this, I've altered the date format from dd.mm.yyyy to dd/mm/yyyy so that Excel will take it as a real date rather than text.
Then I have copied the same data to the cells below for the next day (A33:A63).
I've then adjusted the formula in D2 to calculate properly on change of day
=IF(A2<>A3,"",IF(C3>C2,B3-B2,""))
Then to get to sum on change of day, put this in E32
=SUM(D2:D32)
Then select E2:E32, drag down to E63, you should now have a total for day two.