PROFIBUS
BK3520
 
PROFIBUS DP “Economy plus” Bus Coupler, fibre optic BK3520
Address selector
Configuration interface
Power LEDs
Input for
power contacts
Power contacts
Bus Coupler
supply
K-bus
Fieldbus signal input 1
Fieldbus signal output 1
Fieldbus signal input 2
Fieldbus signal output 2

BK3520 | PROFIBUS DP “Economy plus” Bus Coupler, fibre optic

The BK3520 “Economy plus” Bus Coupler links a fibre optic PROFIBUS system to the modular, extendable electronic Bus Terminal system. With the K-bus extension technology up to 255 spatially distributed Bus Terminals can be connected to one Bus Coupler.

The particular feature for the BK3520 Bus Coupler is its fibre optic connection and its high transmission rate of up to 12 Mbaud. The fibre optic link guarantees that the transmission is free from electromagnetic interference and provides full electrical isolation.

An interface-module is necessary to translate between the physical properties of RS485 to those of an underlying optical fibre ring. The topology corresponds with the RS485 physics (line topology). For this reason, the BK3520 possesses two transmitters and two receivers. The address is set by the address selection switch. The baud rate is automatically recognised. Baud rates of up to 12 Mbaud are supported, so that the transmission speed can be adapted to meet the needs of the particular technical process.

The “Economy plus” Bus Coupler has been designed to accommodate automation requirements. PROFIBUS protocols omit FMS operation in order to be able to transfer more user data in DP mode. The BK3520 incorporates the PROFIBUS DP V1 services.

System data PROFIBUS | BK3520
Number of I/O stations 100 with repeater
Number of I/O points approx. 6,000, depending on the master
Data transfer medium shielded copper cable, 2 x 0.25 mm²
Max. cable length
1,200 m 1,000 m 400 m 200 m 100 m
Data transfer rates
9.6/19.2/
93.75 kbaud		 187.5 kbaud 500 kbaud 1,500 kbaud …3, 6, 12 Mbaud
Data transfer time
approx. 3 ms (10 stations for 32 bit input and output each) approx. 0.5 ms
Technical data BK3520
Number of Bus Terminals 64 (255 with K-bus extension)
Max. number of bytes fieldbus 128 byte input und 128 byte output
Digital peripheral signals 1,020 inputs/outputs
Analog peripheral signals 64 inputs/outputs
Data transfer rates automatic detection up to 12 Mbaud
Bus interface 4 x HP-Simplex sockets (HP-Simplex plugs ZS1031-3500 included)
Topology line topology
Data transfer medium APF (plastic) fibre (1,000 µm)
Power supply 24 V DC (-15 %/+20 %)
Input current 70 mA + (total K-bus current)/4, 500 mA max.
Power contacts 24 V DC max./10 A max.
Electrical isolation 500 Vrms (power contact/supply voltage/fieldbus)
Distance between stations 40 m
Operating/storage temperature 0…+55 °C/-25…+85 °C
Relative humidity 95 %, no condensation
Vibration/shock resistance conforms to EN 60068-2-6/EN 60068-2-27/29
EMC immunity/emission conforms to EN 61000-6-2/EN 61000-6-4
Protect. class/installation pos. IP 20/variable