Enumerations

There are two general approaches to creating an Enumeration.

If you are making a "standalone" enumeration, you can simply create a VTU each time. In practice, we tend to do this more when we can creating enumerations for observables that typically have numbers. For example, we might do this for position if we wanted to represent HERE and NOT_HERE.

In the other case, you may wish to "share" your enumeration literals. How many different definitions of ON, OFF , and STAND_BY do you need? Considering that some systems do not have STAND_BY - don't ON and OFF still carry the same semantic? In this case, you may wish to have a share a VTU that defines these enumerations and then use an Enumeration Constraint to choose the subset of enumerations that you wish to include.