GB/T 20540.4-2006

This standard specifies the data link layer protocol for PROFIBUS fieldbus networks, defining how devices on the factory floor establish communication links, manage data frames, and handle error detection. It is applied in industrial automation systems, such as manufacturing plants and process control environments, where PROFIBUS connects sensors, actuators, and programmable logic controllers (PLCs) for real-time data exchange. Engineers and procurement professionals use this standard to ensure interoperability and reliable communication between field devices from different vendors.