摘要：为促进我国现代化农业发展，实现农业管理的高效性和科学性，设计了一种基于LON平台的现代农业全分布式监控系统，系统由现场采集层、数据通信层和远程数据处理中心层3层组成。系统的现场采集层采用LON平台实时监控农业现场参数，数据通信层依托以太网和GPRS通信终端，实现了农业现场与远程数据处理中心的信息交互，远程数据处理中心层通过科学计算得出农业策略。重点对LON平台的重要设备网关节点的原理模型、核心硬件和软件进行了分析，网关节点在Host Based架构模式下通过Slave_A模式并行接口实现虚拟令牌乒乓式数据通信，完成了LON现场总线与和RS232串口总线的无缝衔接。
关键词：现代农业;LON平台;Host Based架构;Slave_A模式;虚拟令牌传递
Monitoring System of Modern Agricultural Distribution Based on LON Platform
Abstract： In order to promote the development of modern agriculture in China and achieve efficient and scientific agricultural management， a monitoring system of modern agricultural distribution based on LON platform was designed. The system was consisted of field acquisition layer， data communication layer and remote data processing center layer. The field acquisition layer of system can achieve real-time monitoring of agricultural field parameters using LON field bus. The data communication layer of system can realize information interaction between the agricultural field and remote data processing center relying on the Ethernet and GPRS communication terminal. The remote data processing center layer of system can produce agriculture strategy through scientific calculation. The core equipment of gateway node on the LON platform has been dissected mainly with principle model， key hardware and key software. The Host Based architecture of gateway node can realize seamless connection between LON bus and RS232 serial bus using Slave_A model of parallel interface with ping-pong passing mechanism of virtual token.
Key words： modern agriculture;LON platform;Host Based architecture;slave_A mode;virtual token passing
当今世界农业发展的新潮流是由信息技术支持的根据空间变异，定位、定时、定量地实施一整套现代化农业操作技术与管理的系统。基于LON平台的现代农业全分布式监控系统依托LON现场总线网络技术平台，LON平台致力于绿色节能和智能管理，为不同设备的集成并网提供了有效可行的实施方案。LON总线采用数字传输技术，能够有效地防止数据传输的错误发生率，同时工程施工量小，采用的通信电缆少，无需中继就可以将数据传输到千米之外，这种完全分布的系统结构非常适合在农田中应用。
1 系统设计架构及监控过程原理
