Speaker
Description
The Linear IFMIF Prototype Accelerator (LIPAc) is jointly developed by Europe and Japan. The RFQ and its cooling system were procured by INFN-LNL, Italy, and delivered to Japan as an in-kind contribution. The cooling system is a complex subsystem consisting of six pumps with multiple temperature-control loops and is controlled by a hybrid Schneider-Siemens PLC architecture. Since commissioning in 2018, it has supported reliable RFQ operation through local control and EPICS-based supervisory control.
A major challenge arose when the company that designed and manufactured the cooling system ceased operations. As a result, detailed design information, including PLC ladder programs, and vendor support became unavailable. The integrated Japanese-European team operating LIPAc was therefore required to maintain a critical subsystem whose functionality and interfaces were only partially documented.
To address this issue, the joint team has collaborated with a Japanese engineering company experienced in accelerator control systems and EPICS integration. The existing system was investigated to reconstruct undocumented interfaces, including the boundaries between local control, supervisory control, and protection functions. The recovered interface definitions and system functions formed the basis of a modernization plan to replace the obsolete Schneider PLC with a maintainable Siemens platform. The project has now entered the detailed design phase.
This contribution presents the investigations and engineering studies carried out to reconstruct lost interface definitions from operational knowledge and remaining system assets. The challenges encountered, lessons learned, and their relevance to future accelerator projects requiring long-term support of internationally developed systems are discussed.