SI-PROFINET RT User Guide
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Issue Number: 2
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Electrical installation
4.1
Bus media
The SI-PROFINET RT option module incorporates two 100 BASE-TX RJ45 interfaces
operating in full duplex mode with auto crossover correction.
Both ports have integrated switches and can be connected to other PROFINET devices
to create a line network.
4.2
Cabling considerations
To ensure long-term reliability it is recommended that any cable used is tested using a
suitable Ethernet cable tester, this is of particular importance when cables are
constructed on site.
When installing fieldbus or communications cables (especially high speed data cables
such as PROFINET), consideration should be given to the physical layout and
positioning of the cables, in particular the positioning with regards to other cables
(power cables etc.). The recommended distances between different category cables is
shown in
Cables belonging to the same category may be placed adjacent to each other with no
danger of cross-interference.
Similar category cables can be installed in an earthed metal cable tray / trunking
separated from other category cables by earthed metal partitions, provided the cable
tray or trunking has a lid so the cables are completely surrounded in an earthed metal
enclosure.
Figure 4-1 Recommended cable distances
Cables should not be distorted, stretched, crushed or otherwise damaged in any way as
this may cause future reliability issues.
Category I – sensitive and safe cables.
Communication cables
Data cables
Low voltage power (AC up to 25V / DC up to 60V)
Category II – medium voltage cables.
Cables carrying AC voltages between 25V and 400V
Cables carrying DC voltages between 60V and 400V
Category III – high voltage cables.
Cables carrying AC or DC voltages above 400V
Motor / drive inverter cables
Category IV – water industry cables.
Any cables at risk of direct lightning strikes (e.g. cables running outside, between buildings)
Cable
Category I
Cable
Category II
Cable
Category III
Cable
Category IV
> 10 cm
> 10 cm
> 50 cm
> 50 cm
> 50 cm
> 20 cm