Bus termination
At both ends of each segment the bus is terminated by terminating resistors.
To ensure trouble-free operation, make sure that voltage is applied to both bus
terminations at all times.
The terminating resistors are located in the PROFIBUS connectors and can be activated
by moving the slide switch to 'On' .
Fig. 2: Bus termination
Cable data
The cable length specifications refer to the cable type A described in the following:
Data
Characteristic impedance
Capacitance per unit length
Loop resistance
Core diameter
Core cross-section
It is preferable to use a 9-pin D-Sub connector for PROFIBUS networks incor- porating
RS485 transmission technology. The PIN assignment at the connector and the wiring are
shown at the end of this chapter.
PROFIBUS-DP cables and connectors are offered by several manufacturers. Please refer
to the PROFIBUS product catalog (www.profibus.com) for types and addresses of
suppliers.
When connecting the devices, make sure that the data lines are not reversed. A shielded
data line must be used! The braided shield and the shielding foil underneath (if present)
should be connected to the protective ground at both ends; ensure good conductivity of
the connection.
Route the data line separately from all high-voltage cables.
Probifus-DP description
17
Value Unit
135 to 165 Ω
< 30 pf/m
110 Ω/km
0,64 mm
> 0,34 mm
2
417102396 Rev. 1-10.2019