Note: There is a newer version of this specification see VEC 2.0.2
A ConnectionSpecification is intended to contain the logical information that is usually included on an electrical system connection plan (system schematic). It can either stand alone or detail the information of a NetSpecification. A ConnectionSpecification is a container for various ComponentNodes, Connections and ConnectionGroups. A ConnectionSpecification is used, if requirements for realization of the network should be specified (e.g. should a Net be realized with a single or multiple connection (BUS-Systems)).
Note: Logical information means a ConnectionSpecification doesn’t contain layout information. Layout information can be exchanged by other formats like SVG, PDF or DXF.
A ComponentNode is a representative for an element in the electric system, e.g. an actuator, a sensor, an ECUs. In this way it is quite similar to a NetworkNode and may even reference the corresponding NetworkNode in this case. Moreover, a ComponentNode can define childNodes in order to describe its internal structure.
There is no general rule if inliners shall appear in the system schematic or not. In many cases there is a detail of the physical design of the harness (like splices). Their creation is done implicitly when an electrological design is routed into a specific topology and the routing crosses an inliner definition of the topology. In these cases, the inliner definition should not appear in the system schematic. However, there are other scenarios where the inliner definition is done on purpose and as part of the electrological design (e.g. for providing a pluggable modularity in the system). In these cases an inliner can appear in the ConnectionSpecification.
A ComponentNode can specify various ComponentPorts. Each ComponentPort can reference its corresponding NetworkPort (if it has one).
Connections represent the physical realization of a Net (without a topology). A Net (e.g. the BODY-CAN-BUS) can be realized by one or more physical connections (e.g. a CAN-BUS is normally realized by two physical connections (HI & LOW)). The Connections do not define a topology of the realization. This means that a CAN Connection with three ConnectionEnds can be realized in different ways (e.g. three wires with splice, two wires with a double contact or an IDC / IDS contact).
A ConnectionGroup references two or more Connections expressing the physical realization of the referenced Connection shall be somehow grouped e.g. twisted. For complex structures a ConnectionGroup can specify subgroups. Finally, a ConnectionGroup can reference a NetGroup in order to express a refinement-relationship.