Concepts For Retrofitting Industrial Programmable Logic Controllers For Industrie 4.0 Scenarios

In the course of the fourth industrial revolution, companies are facing considerable challenges, such as retrofitting and integrating existing, mission-critical automated production systems (aPS) into new interconnected environments. To integrate the production data from aPS and to make it available for data analysis and plant monitoring, relevant data from the programmable logic controller (PLC) of each aPS needs to be accessed and forwarded. These PLCs, at a first priority, control the production plants and ensure reliable production. Due to the long life-cycles of aPS of around 30 years, a huge number of legacy PLCs with limited processing and communication capabilities exists in the field. Therefore, retrofitting concepts that aim to allow access to PLC data need to account for this special, mission-critical role of PLCs. In the context of PLC retrofitting approaches, research currently addresses two domains: on the one hand, abstract Industrie 4.0 architectures are proposed that lack of implementation details. On the other hand, specific retrofitting concepts are presented, which are usually not transferable to other application purposes.Hence, this work aims to fill this gap by deriving generally applicable retrofitting strategies for legacy PLCs for data collection. Five technology-neutral retrofitting concepts based on industrially relevant use-cases were proposed. Three concepts were substantiated on an exemplary basis and their validity shown within a proof-of-concept. Altogether, this work can act as a guideline for retrofitting automation technology to facilitate the integration of legacy systems in Industrie 4.0 scenarios.