This document was created in parallel with the asset administration shell for Compressed Air Systems – Main Control System.
The organization Plattform Industrie 4.0 published the specification Details of the Asset Administration Shell to define the concept and metamodel for asset administration shells. The specification describes every aspect of asset administration shells in detail.
Figure 15 shows an abstract example on the composition of an I4.0 component and the content of an asset administration shell.
Figure 15 – I4.0 Component Consisting of Asset and Administration Shell
An asset administration shell is defined by the Plattform Industrie 4.0 organization as a “standardized digital representation of the asset, corner stone of the interoperability between the applications managing the manufacturing systems. It identifies the Administration Shell and the assets represented by it, holds digital models of various aspects (submodels) and describes technical functionality exposed by the Administration Shell or respective assets.” 
The content of an asset administration shell consists of submodels and properties. “Each submodel refers to a well-defined domain or subject matter. Submodels can become standardized and thus become submodels templates.” 
The content of this OPC UA Companion Specification is linked to the asset administration shell for Compressed Air Systems – Main Control Systems in a specific way. In general, submodels are modeled as subtypes of the FunctionalGroupType of OPC 10000-100.