Introduction to EPICS and the Control System of the Advanced Photon Source

Modern particle accelerators and large-scale physics experiments demand high-performance, distributed, and reliable control systems. Experimental Physics and Industrial Control System (EPICS) is a robust, scalable, and open-source framework used worldwide to build distributed control systems for scientific and industrial facilities. EPICS integrates low-level hardware controllers and high-level applications, allowing users to perform device control, machine operation, data acquisition, and complex workflow execution. This presentation introduces the core components of the EPICS framework, including Input/Output Controllers (IOCs), device supports, Channel Access (CA) and PV Access (PVA) protocols, and user interfaces. The control system of the Advanced Photon Source (APS) is presented to demonstrate how an EPICS-based control system is constructed. The APS global event-based timing system, machine protection system, data acquisition system, and the injection orchestration software are highlighted.