(I applogize if this takes your solution in another direction, but I didn't have time to review all of the otehr correspondance.)
In a similar situation, I'm monitoring a process temperature and when the temperature exceeds a maximum value for more than one minute, then an alarm is sounded (i.e., lights and sirens).
I simply note the system time when the temperature first exceeds the max and then pass this value to the next loop with a shift register
The vi checks during each loop to see if the temperature is still high and if the elapsed time is more than 60 seconds (my loop is on a two second delay to reduce the number of data points).
When the elpased time (current time minus first alarm state) exceeds the allowable time limit, the alarm is triggered.
MEANWHILE, the vi continues to loop, monitor, and update the other 95 temperature and gas sensor displays every two seconds.
Works pretty well - the timing is accurate enough and all of the temperature and gas displays continue to update "live".
(This works equally well for maximum and minimum time and temperature limits.)
