Introduction to the BE-CO Control System

The document is an attempt to fill the gap between the Control System, as provided by the Beams Controls (BE-CO) group, and anybody who needs to work with the Control System. Providing the glue between the particle accelerator physicists and the accelerators' equipment, the Control System is built on a 3-tier architecture made of hundreds of physical nodes and tens of services. After a short introduction of the different physical tiers and of two basic use cases (control of setting values and monitoring of accelerator variables), we cover two core topics, the device-property model and timing. Next, the reader takes a complete bottom-up tour through the controls infrastructure, discovering the technologies used and the architectures in place. In order to give concrete examples, the main applications of this infrastructure are also covered at the end of the document.