Product Description:

The BK1120 bus coupler is produced by Beckhoff within the BK EtherCAT Bus Couplers series. It links an EtherCAT backbone to the Beckhoff slice I/O system, translating deterministic network telegrams into the local K-bus protocol so that discrete or analog terminals can be scanned from a central controller. By serving as the primary interface, the device allows up to 64 terminal modules to share power and communication resources on a single 35 mm DIN rail, simplifying panel wiring in distributed industrial automation cells.

The EtherCAT interface communicates at 100 Mbaud through two RJ45 sockets that support line or ring topologies without additional switches. Each scan cycle can transfer 1024 input bytes and 1024 output bytes, which the coupler maps to a maximum of 8192 digital I/O points and 256 analog I/O channels. Internal arbitration keeps these data blocks synchronized across the K-bus, providing the controller with consistent, cycle-accurate updates. The terminal stack supports up to 64 positions. Hot-swap detection allows individual terminals to be replaced while the remainder of the segment stays online.

The local backplane is energized by a K-bus supply of 1750 mA, while the electronics that operate the EtherCAT interface require no more than 500 mA from the 24 V DC system supply. Separate 24 V DC power contacts can deliver up to 10 A to high-current output terminals, isolating load circuits from the logic plane. The housing meets the IP20 protection class, so the coupler is intended for installation inside an enclosure that provides suitable protection from dust, moisture, and accidental contact. All wiring and power feeds are routed from the front of the unit, maintaining accessibility when the module is clipped onto the standardized 35 mm rail between adjacent Beckhoff I/O terminals.