基于Modbus／TCP的分布式I／O在列车驾驶模拟器上的应用

为了解决列车模拟器操控台上的人机接口与模拟器主机之间的实时数据传输问题，针对传统的I／O板卡体积大、成本高、维护困难等不足，提出了一种基于Modbus／TCP的分布式I/O系统解决方案。详细地介绍了Modbus／TCP协议的技术特点，开展了系统的具体性能要求分析，选取贝加莱公司的X20系统搭建了硬件平台，并以其配套的AS软件为开发平台，使用C语言编写了程序，并最终应用于上海轨道交通7号线列车模拟器上。现场运行结果表明，该系统运行稳定，实时性能符合要求、兼容性好，并能直接应用于其他线路的列车模拟器上。

Application of distributed I/O system based on Modbus/TCP protocol in train simulator

In order to solve the problem of real time data exchange between the human-machine interface of train simulator console and train simulator host computer, a solution of the distributed I/O system based on Modbus/TCP was proposed, aiming at overcoming the disadvantages of the traditional I/O interface card such as the large bulk, high cost and difficult maintenance. Firstly technical characteristics of Modbus/TCP protocol were introduced in detail. After the analysis of the performance requirement of the system, X20 system of B ＆ R was selected to establish the hardware system. Based on the AS platform of B ＆ R and made use of C programming language, the software was programmed. Finally, the distributed I/O system was applied to the train simulator of Shanghai Metro Line 7. The results indicate that the system is stable, reliable and well compatible, and it meets the real-time performance requirement. The system can be apphed to the other train simulator directly.