BK9000 by Beckhoff

The BK9000 is an Ethernet bus coupler produced by Beckhoff for distributed I/O systems. The unit sits between the Ethernet network and modular I/O terminals, translating network telegrams into K-bus data so distributed sensors and actuators can communicate with a central controller over standard Ethernet cable. It also supplies power to the connected bus terminals and transfers their process data to and from the controller. These functions support deterministic communication and reduce the amount of wiring required in machine-level automation systems.

Ethernet signaling operates at 10/100 Mbaud, and the front panel provides one RJ45 port for the network connection. The port accepts an Ethernet cable containing four twisted wire pairs. The coupler exchanges data for up to 512 digital input and output points and an additional 128 analog input and output points with the controller. The input and output process images each provide 512 bytes for transferring data from high-density sensor arrays, actuators, and other connected field devices. Dielectric isolation of 500 V separates the field wiring from the logic supply, while a permitted network segment length of 100 m supports installation across large machines without intermediate repeaters.

The internal regulator supplies K-bus power to the attached terminals at a maximum current of 1,750 mA. This capacity supports as many as 64 bus terminals before another coupler or power supply terminal is required. Separate power contacts deliver actuator current at a maximum of 10 A, and the connected loads may operate at up to 24 VDC. The electronics operate from a regulated 24 VDC supply connected through the upper terminals. An IP20 housing protects against accidental contact with hazardous internal parts but does not provide protection against water or fine conductive debris. The coupler must therefore be installed inside a suitable control cabinet with adequate space for wiring ducts and ventilation.