The format of the ACTIVITY1 function is:
The function connects the Start, Finish and Duration of a Relation, and controls, through the value pin, the existence of the Relation, based on the Global Time in the model. Consistency is maintained among StartDate, FinishDate and Duration, so that, for example, the maximum Duration cannot be greater than the difference between the mimimum StartDate and the maximum FinishDate. If a Duration is not given, a value will be found by searching up the parent hierarchy of the Relation to which ACTIVITY1 is connected.
As GlobalTime changes, different values of Existence will flow out of the ACTIVITY1 operator to its associated RELATION2 operator.
If GlobalTime is a single value less than the minimum StartDate, or greater than the maximum FinishDate, the Existence value will be False (the Relation does not exist for those values of GlobalTime). If GlobalTime has a single value which is greater than the maximum StartDate and less than the minimum FinishDate, the Existence value will be True (DoesExist). For other cases, the Existence value will be UKE (MayExist), as in the diagram.
A change in any input/output may change any other input/output. A reduction in range of
the StartDate will usually result in a reduction in range of the FinishDate, and vice
versa. Depending on the ranges available, a reduction in range for the Duration may occur.
The value of FINISH is defined as StartDay + Duration - 1, so FinishDate will occur on the evening of the last day, and