InfoPath Dev

Hello, Really stupid question, but I just can't remember the right mechanism for this. I have 3 fields as part of a repeating table; START_TIME, END_TIME, TOTAL_TIME. Where can I set the rule to run the formula to calculate the total_time? If it's the default value for total_time, it creates an error as soon as the start_time is entered (because the end time isn't there yet).

 I'd add a rule to Start Time - condition would be that Start Time and End Time are not blank. Then I'd add the same rule to End Time - same condition, Start and End Time are not blank. Then the rules can set the Total Time.

Hi Hilary, I take it that my confusion over your reply is due to the fact that I had no idea InfoPath can't subtract two times and return an integer value. So I tried following the method at http://www.bizsupportonline.net/infopath2003/time-calculations-infopath-using-rules.htm, which is EXACTLY what I need to accomplish. However, following this example to a tee, I don't return a value in my Total_Time field.