Installation 23/84
3 842 540 399/2016-11, MIT: ID 200,
Bosch Rexroth AG
5.4.6
Cable
The bus cable is specified as cable type A in the EN 50170 and can be used in
accordance with the following table. For the sake of completeness, the cable
parameters and lengths for cable type B are also shown in the following two tables.
When creating new plans for a system, only cable type A should be used due to the
increased total cable length.
The cable parameters are as follows:
Parameter
Cable type A
Cable type B
1)
Cable design
two-core twisted, shielded
Capacitance (pF/m)
< 30
< 60
Characteristic impedance (
Ω)
135…165
100…130
Loop resistance (
Ω/km)
110
–
Core diameter (mm)
> 0.64
> 0.53
Core cross-section (mm
2
)
> 0.34
> 0.22
1) Avoid using cable type B where possible.
Only use shielded, twisted two-wire cables (twisted pair).
Optimal EMC interference immunity can only be achieved when shielded cables
are used.
5.4.7
Transmission rates and cable lengths
The permissible length of the transmission cable in a bus segment is determined
mainly by the following parameters:
• Type of bus cable used
• Transmission rate
• External interferences
• Number of bus users
Detailed information on Profibus installation topics is available at
www.profibus.de, for example.
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