Communications Card Description ZB4-604-IF1, PROFIBUS-DP 5-5
Moeller 07/01 AWB-C2700-1347GB
4.2 Bus cables
The data transmission media of a PROFIBUS network consist of shielded twisted pair cables. Use only line
type A cable as specified in the PROFIBUS standard (EN 50 170).
Impedance : 150 Ohm (135 to 165 Ohm)
Capacitance/unit length : < 30 pF/m
Loop resistance : > 110 Ohm/km
Core cross section : ≥ 0.34 mm
2
(22 AWG)
Recommended PROFIBUS-DP data cable: ZB4-900-KB1
4.3 Cable Lengths
The physical interface of PROFIBUS is based on the EIA Standard RS-485 (differential voltage
transmission). The cable length limits and recommendations meet these requirements.
The following bus segment lengths are possible for line type A cables compliant with the PROFIBUS
standard (EN 50 170).
Baud rate in kbit/s Length in m
9.6 1200
19.2 1200
93.75 1200
187.5 1000
500 400
1500 200
12000 100
Transmission errors may occur if these limits are not observed.
4.4 Shield Connection/Potential Equalisation
The PROFIBUS network requires the use of shielded twisted pair cable. At each station the braided
shield must be connected to the shield reference potential with as little impedance as possible.
The connection between the cable shield and the shield reference potential (metal housing of the
Touch Operator Panel) must be made via the plug connector housing and the fixing screws of the
D-subminiature plug.
The shield reference potential of the individual bus stations is mainly connected to the protective conductor
system. This may give rise to potential differences with resulting compensation currents in the cable shield.
Provide a potential equalisation bar if the potential differences and compensation currents between the
shield reference potentials are high.
To Next Page
Loading...