Design of equipment interlocking control system for LEAF

BackgroundLEAF is a heavy ion experimental facility with low energy, high intensity and high charge state. It belongs to the strong current linear accelerator, and its maximum beam power can reach 10 kW. High-power beams can pose a great risk of damaging field devices in continuous beam mode due to high-power beam bombardment. In order to ensure the safe operation of field devices and key equipment, an interlocking control system for LEAF is designed by using the control board of FPGA and PLC controller.
MethodsThe FPGA-based interlock system mainly implements the real-time monitoring of the arc fault signals from the RFQ cavity, a few fast fault signals from LLRF system and beam diagnostic system. When a valid fault signal is detected, the system will send its protection instruction to the chopper power supply to cut off the beam rapidly. The PLC-based interlock system mainly handles the fault state detection and safety operation of field devices with a slower protective action, and the action time is in a millisecond range.
ResultsThe protective action time of the FPGA interlock system has been achieved within 10 µs. This system adopts two sets of control and protection logic, which are implemented in the control board of FPGA and the PLC controller. It can ensure the safety of the core devices through the double-redundant beam-cutting actions if the key equipment fails or the beam parameters are abnormal.
ConclusionThe complete system has a simple structure. The redundant technique is used in the design of the control protection logic and data transmission path. This provides a reliable safety measure for beam commissioning and physical experiment of the LEAF facility.