For railway transportation, driving safety is the first priority, especially for high-speed railways. As the running speed of trains increases, various risk factors that may be encountered also increase. The high-speed rail line is susceptible to strong winds and heavy rains. In order to ensure driving safety and improve transportation efficiency, it is necessary to build a weather monitoring system that includes wind and rain, so that high-speed railways have the ability to resist disasters under strong winds and heavy rain. In the past, when the train was running at a low speed, it was mainly driven by people. When there were obstacles on the line, from the visual detection to the stop of the train brake, the time and distance can still ensure safety, and there are fewer accidents. When high-speed railway trains run at speeds of 250km/h and above, visual observation can no longer guarantee driving safety, and the danger is greatly increased. Therefore, the impact of falling objects on driving needs to be considered.

Monitor and alarm the natural disasters (wind speed and direction, rainfall, snowfall, earthquakes), foreign body intrusion limit, rail temperature, etc. that endanger the safety of the passenger dedicated line, and provide processed disaster warning, speed limit, shutdown and other information, for The operation dispatching station adjusts the train operation plan, provides the basis for the order of driving control, emergency rescue, maintenance management, etc., and at the same time, realizes the automatic or manual control of the driving speed through the signal system, train control system or driving scheduling command to ensure the safety of high-speed trains. Efficient and comfortable. The railway department refers to the above-mentioned system equipment as "disaster prevention and safety monitoring".

The disaster prevention system is an integrated system of the wind monitoring subsystem, the rainfall monitoring subsystem, the earthquake monitoring subsystem, and the foreign matter intrusion limit monitoring subsystem.

Application of NA-PLC in Railway Safety and Disaster Prevention Monitoring System

The railway safety and disaster prevention monitoring system is composed of multi-level transmission, namely: sensor → monitoring unit (the main controller is PLC) → upper monitoring host (data center) → various terminals (display). The sensor is mainly composed of wind, rain, snow, earthquake, foreign body intrusion limit sensor, etc. In addition to the foreign body intrusion limit sensor is a switch quantity, the other sensors are digital quantities transmitted through RS485; the monitoring unit mainly collects data from various sensors , And pre-process, package the data, and then transmit the data to the data center via Ethernet (TCP/IP), and the data center then stores the data to the database and sends it to each terminal.

• The data type of the on-site meteorological sensor is mainly digital data of RS485 type;
• The data type of the on-site foreign body intrusion sensor is the switch value, which is about 24 points DI and 16 points DO;
• The sensor data is judged, pre-processed, packaged, etc.; the packaged data is transmitted to the upper monitoring host (data center) via Ethernet;
• Receiving the commands sent by the upper monitoring host, and controlling the I/O output.