All-electronic computer interlocking system mainly consists of interlock host and all-electronic execution units which are composed of a total of 11 kinds of control modules: switch machine module, signal module, track module and so on. According to security, real-time and closed characteristics of system communication, the communication protocols between interlock host and all-electronic execution units are designed based on the analysis of the information which is needed to exchange between interlock host and switch machine module, signal module and track module. By taking such measures as setting the source and destination addresses, packet type code, frame serial number and adopting delay invalid and 32-bit CRC, the communication protocol has effectively eliminated duplicate, delete, insert, wrong order, delay and other hazards in the communication between interlock host and the all-electronic execution units. By analyzing and calculating the communication protocol, the result indicates that the hourly dangerous failure rate of the protocol is less than 1. 9×10-11. So its safety is far higher than the requirements of European safety standards SIL4. At present, the all-electronic computer interlocking system adopted this protocol has been opened and applied in several stations; the operation is safe and reliable.%全电子计算机联锁系统主要由联锁主机和全电子执行单元组成,全电子执行单元由转辙机模块、信号机模块、轨道模块等共计11种控制模块组成.在分析联锁主机与转辙机模块、信号机模块、轨道模块需要交换信息的基础上,根据系统通信的安全性、实时性和封闭性特点,设计联锁主机和全电子执行单元之间的通信协议.通信协议通过设置源地址、目标地址、报文类型码、帧序列号,采用延时无效和32位CRC校验码等措施有效地消除了联锁主机与全电子执行单元通信中存在的重复、删除、插入、错序、延时等危害.对通信协议分析计算表明:该协议的每小时危险失效率小于1.9×10-11,其安全性远远高于欧洲安全标准SIL4的要求.目前,采用该协议的全电子计算机联锁系统已经在多个车站开通使用,运行安全、可靠.
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