GE Industrial Solutions AF-600 FP Profibus DP - Manual (Page 11)

The length statements in the tables above are valid for network cable with the following properties:
- Impedance: 135 to 165 ohm at a measuring frequency from 3 to 20 MHz
- Resistance: <110 ohm/km
- Capacitance: <30 pF/m
- Damping: max. 9 dB over the whole wire length
- Cross section: max. 0.34 mm2 , corresponding to AWG 22
- Cable type: twisted in pairs, 1 x 2, or 2 x 2, or 1 x 4 wires
- Screening: Copper-braided screen or braided screen and foil screen
Use of the same cable type throughout the entire network is recommended to avoid impedance mismatch.
The numbers on the following diagram indicate the maximum number of stations in each segment. They are not the station addresses, as each station in the
network must have a unique address.
2.1.2 EMC Precautions
The following EMC precautions are recommended to achieve interference-free operation of the PROFIBUS network. Additional EMC information is available in the
AF-6 series Operating Instructions and Design Guides
NB!
Ensure compliance with relevant national and local regulations, for example in protective earth connection.
2.1.3 Connection of the Cable Screen
The screen of the PROFIBUS cable must always be connected to ground at both ends, meaning the screen must be connected to ground in all stations connected
to the PROFIBUS network. It is very important to have a low impedance ground connection of the screen, also at high frequencies. This can be obtained by
connecting the surface of the screen to ground, for example by means of a cable clamp or a conductive cable gland. The frequency converter has various clamps
and brackets to enable a proper ground connection of the PROFIBUS cable screen. The screen connection is shown in the section Connecting the Network.
AF-650 GP/AF-600 FP Profibus DP Operating Instructions
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