基于卫星通信Linux平台SCADA系统CIP协议通信故障处理

Fault resolution of CIP protocol in SCADA system based on the satellite communication and Linux platform

卫星通信具备回传带宽管理功能,对于为同一SCADA网络的不同远端站提供相同、可靠的数据传输具有重要作用。CIP协议为采用不同物理层和数据链路层的各层网络提供统一的应用层协议标准,使得各层网络在应用层实现无缝链接。采用统一、开放的标准数据通信接口进行实时数据传输,利用卫星通信技术组成以太网络,可以实现远端Linux平台下的通讯服务器与现场站控PLC采用CIP协议进行数据通讯。某管道中控MRCI与站控PLC能够建立会话和数据请求,CIP数据包封装正常,但是MRCI不能正常接收相应数据。对该故障原因进行分析,排除了卫星带宽速率因素的影响,确定了WindowScaling功能处于开启状态是导致故障的关键因素,指出若在8.6kbps卫星带宽速率下使SCADA系统数据正常传输,必须对中控MRCI的TCPWindowScaling功能进行关闭处理。

Satellite communication has the function of feedback bandwidth management that is important for the same and reliable data transmission for different remote stations of the same SCADA system.CIP protocol can provide the uniform application layer protocol standard to the physical layer and data link layer that can realize seamless link to application layer.Real-time data transmission with unified open standard data communication interface and Ethernet based on satellite communication can realize data communication between communication server based on remote Linux platform and station-controlled PLC system using CIP protocol.Session can be created and data can be requested between central-controlled MRCI and station-controlled PLC of a certain pipeline.CIP data packets are also encapsulated.However,MRCI can not receive the session.Fault causes are analyzed and the influence of satellite bandwidth rate is excluded.The state opening of Window scaling is the key fault cause.If SCADA system data transmits at satellite bandwidth rate of 8.6 kbps,the function of TCP Window Scaling of central-controlled MRCI will be exited.