Installation
Page 8
Version FELD-V2002.02
PROFIBUS manual
3 Installation
3.1 Connection of fieldbus lines
burster devices with a PROFIBUS option have a
9-pin SUB-D female
connector
for the fieldbus
connection
5
DGND
(CNTR-N) NC* 9
4 NC* (CNTR-P)
RxD/TxD-N RTS 8
3 RxD/TxD-P
(P24) NC* 7
2 NC *(M24)
(Us terminating resistor) VP 6
1 shield
Fig. 8.1: Connector pin
assignment
* NC = not connected
3.1.1 Installation of fieldbus lines
For the PROFIBUS employing RS 485 transmission technology, all devices
are connected in a line structure. The bus line is a shielded twisted pair cable.
The fieldbus line is specified in EN 50 170 as cable type A and must comply
with specific cable parameters. Cable type B also specified in EN 50 170 is
obsolete and should no longer be used.
Parameter value
Characteristic impedance in
Ω
135 to 165 for 3 to 30 Mhz
Effective capacitance
< 30 pF/m
Loop impedance (
Ω
/km)
< 110
Wire diameter (mm) *)
>0.64
Wire
cross-section
(mm
2
) *)
>0.34
*) the wire cross-sections used must be suitable for the connection options on
the bus connector.
For cable type A, the maximum cable lengths for a bus segment depend on
the transfer rate.
Transfer rate
Max. bus segment length
9.6 ... 93.75
kbaud
1200 m
187.5
kbaud
1000 m
500
kbaud
400 m
1500
kbaud
200 m
3000 / 6000 / 12000 kbaud
100 m