Product specifications

Composite Object Types Appendix A Object Types
540 3BDS011222-510 B
The main type object and the formal instance objects can belong to several formal
instance lists (by using several structure aspects on the same object). In the actual
instance, only one physical child object will be created, but it will be shown in all
the wanted structures.
The formal instance lists are placed directly below the top object of the composite
type. The main type object itself must be repeated, using an additional structure
aspect, in each formal instance list where you want the object to be visible.
(When you create a formal instance list object using the Plant Explorer, it will
automatically insert the top-level type object below the formal instance list.)
This allows you to define target structures where only some child objects will be
instantiated and not the top object itself.
Instantiation of Composite Types
The top object is always instantiated below the current insertion point, as for non-
composite types. If there is a formal instance list for the current structure with the
top object inserted and formal instances below it, then corresponding actual
subobjects will be created below the instantiated top object.
If there are formal instance lists that specify instantiation in other structures (or
formal instances directly below a formal instance list), these instance trees will be
placed at the top of those structures.
Instances of the composite type must follow the structure defined by the type, and
instances must be created and deleted as a whole unit. For example, it is not possible
to instantiate only a part of a composite type, or to delete a child object from an
instance of a composite type.
It is allowed to add additional structure aspects or child objects to an actual instance,
without defining corresponding formal instances in the type. The type only defines a
Figure 335. Composite Instance
Independent Instance
Embedded Instance