Page 47 of 82
Date: 27.01.06
7
Profibus configuration
7.1
RS485 interface
The bus interface of the Sensor Profibus Module is a PROFIBUS interface.
Compared with conventional RS232 interfaces, PROFIBUS allows a larger
number of stations and higher transmission speeds and provides greater
interference immunity.
7.2
Bus structure
The bus has a linear structure in which each bus segment has a terminating
resistor at each end. Branch segments can be set up using repeaters (signal
amplifiers).
7.3
Number of bus stations
The PROFIBUS interface allows up to 32 bus stations to be connected
simultaneously in each bus segment. Additional bus segments can be created
using repeaters, taking the maximum number of stations to 127.
7.4
Transmission speed
The transmission speed is detected and set automatically by the Sensor Profibus
Module.
Note:
The permitted line lengths decrease as the transmission speed
increases.
7.5
Bus cable, bus connector and bus terminating resistor
Bus cable
A shielded twisted pair having at least two wires with the following electrical
specification must be used for bus cabling.
Terminating impedance: 100 ... 130
Ω
at f > 100 kHz
Effective capacitance:
max. 30 pF/m
Conductor cross-section: min. 0.34 mm
2
Attenuation:
max. 6 dB over the entire length
Standard:
EN50170
