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GFK-1538H
Bus Installation Guidelines
The proper cable for a Profibus network is a shielded twisted pair cable. Profibus cable is sold as "Profibus Network
Cable". The twisted pair cable consists of a Green and a Red wire. Below are some of the cable characteristics of Profibus
cable.
Network Topology
Medium
Number of Stations
Transmission Speed
Connector
Cable Type
Impedance
Capacity
Resistance
Wire Gauge
Conductor Area
Bus Length
The maximum bus length using shielded, twisted-pair cable for a single network segment is 1200 meters. Total network
length may be increased with the use of repeaters, up to a maximum of 3 repeaters per network. Other cable types may
be restricted to shorter bus lengths. The maximum bus length also depends on the data rate, as shown in the following
table.
Maximum Bus Length in Meters
1,200
1,200
1,200
600
400
200
100
Often, it is the required bus length that determines the data rate.
For data rates up to 500 kbits/second, follow the stub recommendations of Profibus Part 1. At 1500 kbits/second the
overall drop capacity should be less than 0.2nF. The maximum length of the stub at 1500 kbits/second is 6.6 meters.
Cable shielding is recommended at higher baud rates, to maintain communications integrity in the industrial
environment.
Linear bus, terminated at both ends. Stubs possible.
Shielded twisted pair cable. Shielding may be omitted, depending on the environment.
32 stations in every segment without repeaters. With repeaters, extendible up to 127.
9.6, 19.2, 93.75, 187.5, 500, 1500 Kbits, 3 Mbits, 6 Mbits, 12 Mbits.
9-pin D-sub connector
Profibus DP
135 to 165 Ohms (3 to 20 MHz)
< 30 pF per meter
< 110 Ohms per Kilometer
> 0.64 mm
> 0.34 mm2
Kbits per Second
9.6
19.2
93.75
187.5
500
1,500
3,000; 6,000; 12,000
Nov 2019
5
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