A bus coupler (BK + EK) is a device used in automation technology to connect different bus systems with each other. The bus coupler regulates the exchange of data between the different buses and enables the connected devices to communicate with each other.

The BK + EK essentially consists of two parts: the bus system coupler (BK) and the expansion coupler (EK). The BK is connected to the higher-level bus system, while the EK communicates with the connected devices. The BK + EK acts as an interface between these two levels and enables the smooth exchange of data.

The bus coupler fulfills various functions. For example, it can serve as a data distributor that forwards messages from one bus system to several other bus systems. It can also act as a data filter, filtering out certain messages and passing on only relevant information to the connected devices. In addition, the bus coupler can work as a data converter that converts the data formats between different bus systems.

Overall, the bus coupler enables efficient and reliable communication between different bus systems in automation technology. It facilitates integration and data exchange between different devices and systems and contributes to the efficiency and performance of automated processes.