Research On NC-Link Naming Service And Cluster Technology

As the infrastructure of the industrial Internet,the CNC equipment interconnection protocol is usually used for data collection and instruction issuance.In order to adapt the NC-Link protocol to the modern factory environment with complicated types and quantities of equipment,this article aims to solve the efficient realization of service discovery and communication components of equipment communication,and provide basic data services for upper-level applications.Based on the status of industrial Internet research and actual working scenarios,the data types generated by the operation of numerical control equipment and smart factories are studied and metadata suitable for the NC-Link protocol is proposed.Metadata is defined by proto3,and corresponding multiple development platform interfaces are generated.It describes the hierarchical relationship between CNC equipment,components,and data sources,and defines the field names,units,and data types generated by the equipment.The current version of the NC-Link protocol lacks routing and discovery of agents and adapters.Provide naming services for the defined services and their interfaces.The two parties in the communication perform service registration and service discovery respectively.The agent layer registers with the registry based on the services provided.It briefly describes the process of the server registering with the registry and the method of supporting multiple registration protocols.At the same time,it describes the process that the client obtains the server stub data from the registry,and requests the server to implement the underlying implementation and unified encapsulation of the request based on the stub data.Subsequently,the metadata processing and application of the communication interfaces of each role in the NC-Link protocol are developed.Store and parse the metadata configured by the NC-Link protocol for each adapter,device and component according to the level,and start the data processing,analysis and collection of the corresponding component and data item according to the type declared by the metadata.It shields the differences in the underlying data types upwards,making it applicable to devices that generate multiple data encodings.Shield the details of data communication downwards,provide basic control and communication services for the equipment,complete the requirements of the smart factory.Compare and analyze with the traditional cluster communication model.In order to reduce network overhead,and reuse the link as much as possible.The frame division multiplexing mechanism is adopted to multiplex the TCP link,thereby reducing server resource requirements and increasing concurrency.And use streaming requests and responses to implement a publish and subscribe model.So as to meet the server's initiative to communicate with the client.Regarding the proxy and adapter routing selection in the NC-Link protocol,the common load balancing algorithms are sorted and collected,and concurrent load balancing is realized.This paper proposes a sticky hash load balancing algorithm from the perspective of improving communication efficiency to solve the unnecessary overhead of frequent establishment and disconnection of links.It also organizes and implements the fault tolerance mechanism,and provides multiple call failure strategies for the NC-Link protocol.Finally,the implementation of the NC-Link protocol is verified through experiments to prove the validity and completeness of the design.The results show that naming services can provide high availability and fault tolerance.It reveals the selection of the json parser in actual production,the efficiency of the pipe redirection technology used by the adapter process and the embedded process,and the use of the NC-Link protocol for data compression.And comprehensively verified the availability and reliability of the data upload service.Through the stand-alone pressure test to show the maximum stand-alone service volume of the test environment.