PLC used in the train control simulation system

The train control center simulation system is a platform, which can test the reliability, safety of the train control center. On one hand this platform provides the corresponding test on the hardware and software, on the other hand it provides the most close to true circumstance of simulation environment. And the relay simulation frame is just used for simulation of the external relays. For building this relay simulation frame, we choose PLC to structure the hardware part, while we choose C# high-level language to program the PC software. To communicate PC with PLC we use serial port as the communication port and use Modbus as the communication protocol.