RS485 Bus Coupler BK8000
Power LEDs
Bus Coupler
Input for
power contacts
Power contacts
Serial interface
Address selector
Ethernet RJ45

BK8000 | RS485 Bus Coupler

RS485/RS232The BK8000 Bus Coupler usess the physics of the RS485 (V.24) specification for data transmission. Application of the Bus Coupler with a serial interface is suited to those cases in which the use of a fieldbus system can be omitted. The RS485 interface can be used by any automation device with the corresponding interface to gain access to the Bus Coupler. Data exchange is made via an open, documented protocol.

Another mode of operation is for the Bus Coupler to function in master/slave mode as a fieldbus multiplexer. The input data from one device are copied directly to the outputs of the other, without the aid of an additional master – and vice versa.

The BK8000 Bus Coupler communicates via an RS485 interface. This permits a bus to be constructed with up to 99 participating devices (addresses can be set with an address selector).

System data RS485 | BK8000
Number of I/O stations 99
Number of I/O points depending on controller
Data transfer medium screened, twisted copper cable 2 x 0.25 mm² (RS485)
Max. cable length 1,200 m
Data transfer rates 9.6 kbaud, 19.2 kbaud, 38.4 kbaud
Technical data BK8000
Number of Bus Terminals 64
Max. number of bytes fieldbus 512 byte input and 512 byte output
Digital peripheral signals 512 inputs/outputs
Analog peripheral signals 256 inputs/outputs
Protocol open, documented protocol
Configuration possibility via KS2000
Bus interface RS485 D-sub
Power supply 24 V DC (-15 %/+20 %)
Input current 70 mA + (total K-bus current)/4, 500 mA max.
Starting current 2.5 x continuous current
Recommended fuse ≤ 10 A
Current supply K-bus 1750 mA
Power contacts max. 24 V DC/max. 10 A
Electrical isolation 500 V (power contact/supply voltage/fieldbus)
Weight approx. 170 g
Operating/storage temperature 0…+55 °C/-25…+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, GL
Ex marking II 3 G Ex nA IIC T4 Gc
Accessories/related products  
KS2000 configuration software for extended parameterisation
Cordsets cordsets and connectors
BK8100 RS232 Bus Coupler for up to 64 Bus Terminals
RS485 For further RS485 products please see the system overview