Take the time stamp, convert them to seconds using "Date/time to seconds" VI, substract them...and then use "seconds to Date/Time" VI......you will get the difference...........
While David's message #20 is a good example of an elapsed time timer, how is that one the answer to your question?
Your question was how to subtract two times, which is simple enough, but was complicated by the fact you wanted to use the date/time cluster, and show the result in a time stamp, which as Rolf pointed out in message 14, can't really be done because the concept of different months, etc. falls apart when comparing dates and times.
