“Compact” Coupler between E-bus and K-bus Terminals BK1250, EtherCAT
I/O Error K-bus
I/O Run K-bus
Power contact
Bus Coupler
power supply
Error LED 
E-bus Link/Act LED 
Run LED 
+24 V
0 V
+24 V
0 V
Top view 
Bus Terminals
EtherCAT Terminals
extended temperature range

BK1250 | “Compact” Coupler between E-bus and K-bus Terminals

The BK1250 is a “Bus Coupler in terminal housing” for mixed application of EtherCAT Terminals (ELxxxx) and standard Bus Terminals (KLxxxx) in a bus station. It enables implementation of compact and cost-effective control solutions. The wide range of Bus Terminals can thus be optimally combined with the communication speed and large bandwidth of EtherCAT Terminals. Up to 64 Bus Terminals (with K-bus extension up to 255) can be connected to a BK1250. The Bus Coupler recognises the connected Bus Terminals and automatically allocates them into the EtherCAT process image.

Technical data BK1250
Task within EtherCAT system coupling of standard Bus Terminals (KLxxxx) to 100BASE-TX EtherCAT networks
Number of Bus Terminals 64 (255 with K-bus extension)
Max. number of bytes fieldbus 1024 byte input and 1024 byte output
Protocol EtherCAT
Data transfer rates 100 Mbaud
Configuration possibility via KS2000 or EtherCAT (ADS)
Bus interface via E-bus contacts
Power supply 24 V DC (-15 %/+20 %)
Input current 70 mA + (total K-bus current)/4, 200 mA max.
Starting current approx. 2.5 x continuous current
Recommended fuse ≤ 10 A
Current supply K-bus 500 mA
Power contacts max. 24 V DC/max. 10 A
Electrical isolation 500 V (power contact/supply voltage/Ethernet)
Weight approx. 55 g
Operating/storage temperature -25…+60 °C/-40…+85 °C
Relative humidity 95 %, no condensation
Vibration/shock resistance conforms to EN 60068-2-6/EN 60068-2-27
EMC immunity/emission conforms to EN 61000-6-2/EN 61000-6-4
Protect. class/installation pos. IP 20/variable
Approvals/markings CE, UL, ATEX
Ex-Marking II 3 G Ex nA IIC T4 Gc
Cordsets cordsets and connectors