This ReferenceTypecan be used to expose the relation between an Objectrepresenting some functionality and an Objectrepresenting some environment (e.g. hard- or software) which is necessary to execute and run the functionality. This implies that a malfunction in a referred environment or a missing related environment results in a non-functional functionality. A functionality Objectmight relate to several environment Objects, in that case all environment Objects are necessary to execute and run the functionality. An environment Objectmight be referenced by several functionality Objects.

For example, the functionality to move an axis is hosted by the drive moving the axis. Another example is some analog input functionality, which is related to the IO-module and the related firmware.