touble with a time calculation

[richard]

do I understand the problem correctly
I'm assuming we have a set time day-h:m:s.xx ie day 0 hour 2 minute 30 sec 28.34 and that we then subsequently read a clock and calculate the elapsed time between now and the set time if and only if the now time is greater than the set time .
is this right ?

[EarlyBird2]

Richard No.

longpole001's program counts down to set time then counts up after set time.