The Research Of EAST Real-time Network Communication System

With the in-depth development of EAST physics experiments,advanced control contents such as plasma configuration,pressure,divertor thermal load and magnetic fluid instability have been continuously integrated into the plasma control system;in order to achieve the effective control of different time scales from hundreds of microseconds to tens of milliseconds and multi-input and multi-output plasma parameters,it needs to solve the problem of real-time data acquisition and transmission under strong interference and complex electromagnetic environment,develops more reliable real-time network systems and operating systems,supports distributed real-time data acquisition,transmission and storage system.Based on the investigation of real-time network communication systems in tokamak devices at home and abroad,this dissertation combines advanced information technology and uses RedHat MRG-R(Messaging,Realtime and Grid-Realtime)real-time linux as the operating system,which provides deterministic response time and provides real-time customization of the operating system for different real-time control requirements;in order to accelerate the promotion of EAST real-time data collection domestic independent controllable substitution plan,this dissertation combines CPU affinity technology,multi-threading technology,data cache technology and so on to realize multi-channel synchronous real-time data acquisition of multiple ADLINK DAQ PXI-2022 acquisition cards,which can meet the requirements of more than 10kHZ,adopts a reflective memory card(Reflective Memory,RFM)with high speed,good real-time performance and high reliability as the real-time network,and designs a lightweight real-time communication protocol on this basis,to transmit collected data in real time and complete the sending of PCS control commands at the same time,conducts in-depth analysis and research on the data read and write mode of RFM,proposes an optimization method of RFM read and write speed based on"address mapping",solves the problem of slow read and write speed of PCIe interface type,optimizes the read/write speed,from the original 8.6MBps/47.7MBps to the current 51.4MBps/51.3MBps(when reading and writing 512 Bytes),which significantly reduces the real-time transmission delay of data,thus achieving the requirement that the total control delay is less than 100 microseconds.Since RFM network is an optical fiber network,it can overcome strong electromagnetic interference and ensure the lossless transmission of real-time diagnostic data and commands.In order to realize the fast and reliable transmission of massive data,the dissertation designs a real-time transmission and storage mechanism based on "time slice",which effectively solves the bandwidth bottleneck problem of Gigabit Ethernet and meets the needs of synchronous transmission of diagnostic data to the EAST server.In order to ensure the safe and reliable operation of the control network,the dissertation also develops a network monitoring system based on Cacti,which realizes the traffic monitoring of EAST experimental network equipment and the alarm function of faulty equipment,and provides a good monitoring tool for experimenters.The system designed in this dissertation provides a whole set of universal real-time data acquisition scheme and specification for fusion device,which can effectively solve the real-time communication problem in fusion experiment.The work in this dissertation can fully reflect the successful application of the computer hardware and software technology used in the real-time data communication and control of fusion experiment,which has important practical significance and integration innovation.At the same time,the dissertation completed the expansion of the basic structure of the EAST plasma control system in three aspects:real-time operating system,real-time data acquisition and real-time network.It provides more reliable options,which is of great significance for the establishment of independent plasma control system in China.