现场总线是将自动化最底层的现场控制器和现场智能仪表设备互连的实时控制通讯网络，遵循ISO的OSI开放系统互连参考模型的全部或部分通讯协议。FCS则是用开放的现场总线控制通讯网络将自动化最底层的现场控制器和现场智能仪表设备互连的实时网络控制系统
2、现场总线与局域网的区别
（1）按功能比较，现场总线连接自动化最底层的现场控制器和现场智能仪表设备，网线上传输的是小批量数据信息，如检测信息、状态信息、控制信息等，传输速率低，但实时性高。简而言之，现场总线是一种实时控制网络。局域网用于连接局域区域的各台计算机，网线上传输的是大批量的数字信息，如文本、声音、图像等，传输速率高，但不要求实时性。从这个意义而言，局域网是一种高速信息网络。
（2）按实现方式比较现场总线可采用各种通讯介质，如双绞线、电力线、光纤、无线、红外线等，实现成本低。局域网需要专用电缆，如同轴电缆、光纤等，实现成本高。
interface is friendly, and the maintenance is simple;
2. Industria1″ system communication
Industrial” system uses international standard industrial bus. Field controller supports Profibus, FF, ModBus, Can, etc.
International standard fieldbus, Profibus is the most widely used open fieldbus international standard in the world, divided into FMS, DP and PA
Level 3, DP communication rate can be as high as 12Mb. Profibus is used to connect intelligent devices such as distributed I/0 stations and field bus instruments.
Communication between the process station, operator station and engineering station takes place via the system bus DigiNetS (Industrial Ethernet). user
Different transmission media (RJ45 twisted pair, thin, thick or fiber optic cables and mixed media) and network topology can be selected for the system bus.
Simple
