Within the Industry 4.0 paradigm, production systems have shifted into Smart Production Systems controlled through decentralized architectures. To enable the development of decentralized architectures supervised from a central coordinator, it is necessary to define common approaches and vocabularies to facilitate the exchange of real-time data and information among the different manufacturing entities. To face this challenge, a GEMMA-based decentralized architecture is proposed within this paper. A Hierarchical Design Pattern for UR-controllers is introduced to generate code from specifications expressed in accordance with a GEMMA-GRAFCET representation. Then, a PLC-controlled system is integrated with a Universal Robot for the generation of a Decentralized Architecture Supervised from a Central Coordinator. Through a lab case study, it is demonstrated how the proposed approach enables the implementation of a decentralized architecture through the use of a common vocabulary for the management of the operational modes of production systems