Research progress of HL-2M distributed timing system

Abstract

HL-2 M is an upgraded device of HL-2A, focusing on research topics related to burning plasma physics, including plasma confinement and transport, high-energy particle physics, new divertor configurations, feeding in high parameter plasma and interaction between the first wall and plasma, etc. Hundreds of diagnostic and engineering control subsystems will be put into experiments. In the process of plasma discharge, each relatively independent subsystem must be put into operation strictly in accordance with the predetermined schedule. The existing HL-2A timing system can no longer meet the requirements. Precise Time Protocol (PTP) is a mature technology. At present, ITER (International Thermonuclear Experimental Reactor) and other institutions have tested the accuracy of clock synchronization and single pulse triggering. However, according to the actual discharge requirements of HL-2 M, we need to use the customized triggering function of uniform pulse train and non-uniform pulse train based on future time events (FTE). Therefore, a new high precision timing system for HL-2 M needs to be designed.Referring to the design scheme of ITER Time Communication Network (TCN), combined with the actual situation of HL-2 M, the distributed timing system based on PTP has been studied, which can realize multiple triggering functions including single pulse, uniform pulse train, non-uniform pulse train and other arbitrary pulse types to meet the actual needs and improves the clock synchronization and triggering accuracy of HL-2 M timing system from microsecond level to sub-microsecond level, and ultimately better than 100 ns.