Design, implementation, and preliminary testing of the interlocks and safety functions for the CMDS (cryomodule and cryogenic distribution system) master system at the European Spallation Source ERIC

Abstract The current paper introduces the design and implementation of the Interlocks and Safety Functions implemented for operating the cryogenic system of the European Spallation Source (ESS) superconducting Linear Accelerator (LINAC), emphasizing the integration of individual cryomodules and valve boxes within a unified system controlled by a master CMDS (Cryomodules and Cryogenic distribution System) PLC. The study focuses on the practical implementation of these Interlocks and Safety Functions for the entire cryogenic systems in the superconducting LINAC, validating the design with some preliminary tests before cooling down the Accelerator. The paper evaluates the primary goals which include protecting the machine from overpressure or overfilling; electricity, network, or compressed air shortages; control system or instrumentation failure; loss of cryogenics or vacuum conditions; and collecting valuable operator feedback for continuous improvement. The controls architecture for the CMDS is based on one Programmable Logic Controller (PLC) integrated into EPICS through the controls network, and distributing commands and notification via Profinet (PN) to a total of 46 PLCs responsible for the cryogenic controls of the valveboxes and cryomodules in the LINAC. This type of integration allows for the remote operation from the control room and the necessary interaction of the control system with other related systems.