BK3500 | PROFIBUS Bus Coupler, fibre optic, 1.5 Mbaud

The BK3500 Bus Coupler connects the PROFIBUS system to the electronic terminal blocks, which can be extended in modular fashion. One unit consists of the Bus Coupler, any number of up to 64 terminals and one end terminal.

The particular feature of the BK3500 Bus Coupler is its fibre optic connection. The fibre optics mean that the transmission is particularly safe from interference and has absolute electrical isolation.

In order to operate a BK3500 in the PROFIBUS, an interface module is required to translate between the physical properties of 485 to those of an underlying fibre optic ring. A sub ring may contain up to ten BK3500 or other fibre optic modules. The baud rate is set by means of two DIP switches on the Bus Coupler. The fibre optic connection of the BK3500 Bus Coupler behaves like an OLP (Optical Link Plug).

The Bus Coupler recognises the connected terminals and automatically generates the affiliations of the inputs/outputs to the bytes of the process image. The first input/output signal is inserted in the first bit of one byte (LSB), beginning from the left. The Bus Coupler inserts further signals in this byte. Inputs and outputs are clearly separated. The Bus Coupler automatically begins a further byte if the number of inputs or outputs exceeds 8 bits.

PROFIBUS is an open fieldbus system with European standards. The PROFIBUS has a bus structure; up to 126 stations can be operated in a system. Baud rates of up to 1.5 Mbaud are selectable, so that the transmission speed can be adjusted to the demands of the technical process.

Complex signal processing for analog I/Os, position measurement, …

The BK3500 Bus Coupler supports the operation of all Bus Terminals. As far as the user is concerned, handling of the analog inputs/outputs is not different to other series. The information is available in the process image of the controller for processing in the form of a byte array.

The analog and multi-functional Bus Terminals can be adapted to each specific application using the KS2000 configuration set. Depending on the type, the analog Bus Terminals registers contain temperature ranges, gain values and linearisation characteristics. Using the KS2000 software, the required parameters can be set on a PC. The Bus Terminal stores settings permanently and in a fail-safe manner.

Optionally, the Bus Terminals can also be controlled by the control system. Via function blocks (FBs), the programmable logic controller (PLC) or the Industrial PC (IPC) handles configuration of the complete periphery during the start up phase. If required, the controller can upload the decentrally created configuration data in order to centrally manage and store this data. Therefore, new adjustments are not necessary in the event of replacement of a Bus Terminal. The controller automatically sets the required setting on power up.

The Beckhoff GSE and type data files to the Bus Couplers support the Bus Terminal options and can be loaded in the corresponding master configuration software to facilitate planning and design. Various configurations and parameters for the Bus Coupler can be selected via GSE and type data files.