  The MTP is an emerging standard for the software integration of process
modules into a control system. The core concept of MTP is to separate process
plants into autonomous modules called PEA which offer easy to use high level
services. Applying the MTP concept leads to a modular production which can
easily be adapted by adding, subtracting, or exchanging individual units. In
order to leverage this flexibility, it is important to know the capabilities
each PEA offers and expose them in a machine-readable way via its digital twin.
As one realization of this requirement, this paper describes how a semantic
annotation of MTP services using an ontology can be realised in conjunction
with the AAS technology.
