DDFST returns the first, or oldest, value of a daily detail variable within the defined hour range. The hour range is set by StartHour and StopHour.
SYNTAX:
DDFST(Cx, StartHour, StopHour )
where :
Cx is a conditional variable x
StartHour defines the hour to start gathering data for the calculation, using a 24 hour time designation
StopHour defines the hour to stop gathering data, which includes data to the end of the specified hour
EXAMPLES:
V83 = DDFST(V72, 0, 11)
Variable 82 will contain the first value found between Midnight and 11:59 AM, as demonstrated below:
V83 = DDFST(V72, 2, 14)
Recalculating Variable 83 with this new equation, it will now contain the first value found between 2:00 AM and 1:59 PM:
As you can see here, it skips the values found before 2:00 AM. This is due to the StartHour Setting of '2'.