An SME needs to be able to describe and talk about a Facility Asset, whatever the scope of that is, its boundaries, and conditions for connecting them. To meet these needs, the IMF language defines three Elements into the vocabulary: Block, Terminal, and Interface Point.
Definition: Block (B) – A Block B is an object with a collection of attributes used to describe an entity (4).
A Block is visualized with a rectangular box. See Figure . A Block is something that is of interest to the SME. We use the Block to set boundaries of something complex which is convenient to treat as one entity. This could be anything from a whole industry plant, a pump system, or a small location that is of interest.
Definition: Terminal (T) – A Terminal T is an object with a collection of attributes used to describe the input or output of a Block B, and hence its boundaries.
A Terminal is visualized as a small box with a plus (+) sign, as shown in Figure 12. Input Terminals are placed on the left side of a Block while Output Terminals are on the right, facilitating a left-to-right flow. A Terminal cannot exist without a Block. This makes sense because a Terminal is at the boundaries of a Block, and if there is no Block there is no boundary.
Definition: Interface Point (IP) – An Interface Point IP is an object with a collection of attributes used to specify the condition for connecting one Block B1 and its Terminal T1, to another Block B2 and its Terminal T2.
An Interface Point is visualized using two half-moons together forming a circle as shown in Figure 13. An Interface Point shall have at least one Block and its Terminal that together constitutes one side of the condition for a connection. To ‘complete’ an Interface Point, two Blocks and their Terminals are needed. Hence the two half-moons indicating that two conditions (collection of attributes) need to match.
It is useful to think about the Interface Point as a set of equations that must be satisfied.
(4) An entity is a thing with distinct and independent existence.