As with SIMATIC PCS 7, the current Distributed Control System (DCS) from SIEMENS that has impressed customers around the world, the legacy systems have also made process control history. Systems such as TELEPERM M, APACS+, QUADLOG or TI 505 have proven themselves in recent decades with their performance capabilities, reliability, and ease of use in a wide range of industries. Now, many of these installations are reaching the end of their life cycle. A migration to SIMATIC PCS7 is the best step towards the availability of these plants in the future. They protect the continuity of the process control technology investment, increase plant efficiency and extend cost effectively the life cycle of the plant.