Primetals Technologies is modernizing the entire process control system at Voestalpine’s LD3 steel plant in Linz in Austria. In June 2022, voestalpine completed the first modernization phase. In this first part, process control systems for the three converter lines were updated. Updating the entire process control system will lead to improvements in both investment security for the steelworks and process automation availability. Involving more than 100 individual process control systems, the project will be completed in 16 phases and will run until the end of 2022.The first phase of the modernization project covered control systems for the three converter lines and for the higher-level converter area. Upgrading systems for secondary metallurgy, slab treatment, and dedusting units will follow in coming phases. Before a new process control system goes into operation, a system test is carried out using a "digital twin", which is a digital test and simulation environment with all the functions of the production system.The old process control system of Voestalpine’s LD3 steel plant is based on the SIMATIC PCS 7 system and possesses a large number of software libraries. Voestalpine’s process control system is one of the largest PCS 7 installations worldwide. While updating the entire control system, Primetals Technologies will take over the existing libraries. This saves time spent on extensive testing of important functions in all units and avoids long plant downtime.The new process control system ensures the availability of electronic spare parts, improves operational reliability, and ensures long-term compatibility with the latest hardware and software. Throughout the project, detailed documentation will ensure that existing process control system certificates remain valid after the conversion.