OBJECT ORIENTED PLC OBJECTS
The objects are defined following a physical model, the relay
component, having the same properties of the relays used in modern
electrical cabinets. Physical relays are split in two components, a
single type of connecting base, common to all types of relays (which
ensures direct replacement of parts), and a specific control block
which is plugged into the base, and implements the functionality of
each type of relay. Besides, following the physical model, a new
conductor component is defined. This conductor can carry any kind
of signal defined in the IEC standard (Bool, Integer, Real, Time,
etc.), and it is used to connect the objects regardless the kind of
signals due to the standard common base.
WIRES
As in electrical cabinets, the components are connected to each
other through wires. Hence, in this paper three levels of wires are
defined User Defined Data types. The definition of these three levels
allows the user to apply different OOP features: