The decade long transition from a custom control system to EPICS

The Karlsruhe Research Accelerator (KARA) at the Karlsruhe Institute of Technology in Germany has been in operation for over 20 years now. It originally started with a custom control system using custom hardware control boards. After adding a second independent control system to be able to handle PLCs, the arrival of new diagnostics for the accelerator with built-in EPICS support triggered the decision to fully migrate to EPICS. After a period of over 10 years the very last remaining parts of the original control system were switched off this year. This presentation will discuss the process of this decade long transition process.