Product specifications

Building Object Types
494 3BDS011222-510 B
The General Properties aspect and the Operating Manual aspect are required by the
object type, and cannot be deleted from the instance.
If an aspect on the object type is changed, the change will be propagated to all
instances, unless the aspect on an instance has been overridden by a local change.
Subtype Creation and Object Type Extensions
The object type system allows an object type to be extended in two ways,
either with a subtype or with an object type extension.
An instance from a subtype inherits its type rules from both the subtype and from
the supertype. An object type extension adds more type rules directly to an object
type. The major difference between subtyping and object type extension is that
instances created from the supertype are not changed when subtyping it,
but an object type extension on an object type changes all created instances.
An example makes the statements above a little bit easier to understand.
Figure 301. New Aspect Dialog Box on a Cell Information Instance