Characteristic features

Characteristic features

The various application fields, for example control, factory automation, power distribution, building
automation, primary process industry, etc, have the following characteristic bus requirements:
• network topology: linear bus with or without terminator, including drop cables and branches (tree)
• medium, distances, number of stations: depending on the signal characteristics, for example, for
shielded twisted pair, ( 1.2 km without repeaters, 32 stations)
• Transmission speed: depending on network topology and line lengths, for example, step-wise from
9.6 to 500 kbits/s
• redundancy: second medium is optional
• addressing: 0 to 127 (127 = global addresses for broadcast and multi-cast messages), address
extension for regional address, segment address and service access point, (LSAP), 6 bit each
• station types: masters (active stations, with bus access control); slaves (passive stations, without
bus access control); preferably at most 32 masters, optionally up to 127, if the applications are not
time critical
• bus access: hybrid, decentral/ central: token passing between master stations, and master-slave
between master and slave stations
The Profibus user organisation includes the following members: AEG AG; Robert Bosch GmbH;
Endress + Hauser GmbH + Co; Khockner-Moeller GmbH; OMRON Electronics GmbH; Siemens AG;
Weidmuller GmbH.

Set up in December 1989, the intention of the organisation is that:
• the exchange of information of all parties interested in the Profibus is to be supported
• the work on draft standards for further development of the Profibus concept will continue
• projects concerning the extension of functions will be supported
• the right of qualified and tested products to carry the name Profibus will be introduced and supervised
• public relations to inform all parties interested in Profibus standards