Here the way using the IF and NOW() functions
Cells used A1 & B1 where A1 is the result of the scanner and B1 is your
formula.



=If(A1<0,Now(),"")
This will work if you don't mind having another column.

TVCCBJB wrote:
I use a scanner in my classroom to record attendance. Students highlight the
cell next to their name on a roster then scan their ID. It enters their ID
number in the cell. I would like the time the card was scanned to show up
instead. I played around with the If and Now formulas but could not get it to
work. I'm thinking of a macro that whenever any value is entered in the cell
it shows time instead. Any ideas?