Profibus-Dp Interface; Rs-485 Technology Transfer - Siemens RWF55.5 User Manual

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Building Technologies Division
Infrastructure & Cities Sector

12 Profibus-DP interface

12.1 RS-485 Technology transfer

Transmission is carried out in accordance with the RS-485 standard. This covers all
areas in which high transmission speeds and simple, inexpensive installation
technology are required. A twisted, shielded copper cable with a wire pair is used for
this purpose.
The bus structure enables non-reacting coupling and decoupling of stations or gradual
commissioning of the system. Subsequent extensions have no effect on stations that
are already in operation.
A transmission speed of between 9.6 kbit/s and 12 Mbit/s can be selected. This is
selected as a standard value for all devices on the bus during system commissioning.
Network topology Linear bus, active bus terminator at both ends, branching only
permitted with baud rates of <1.5 Mbit/s
Medium Shielded, twisted cable
Number of stations 32 stations in each segment without repeaters. With
repeaters, can be extended to 126 (maximum of 9 repeaters
permitted)
Connectors Preferably 9-pin D-Sub connectors
All devices must be connected in a line structure. Up to 32 nodes (masters or slaves)
may be interconnected within this kind of segment. If there are more than 32 nodes,
repeaters must be used (to increase the number of devices, for example).
The maximum cable length depends on the transmission speed. The cable length
specified can be increased by using repeaters. It is recommended that you do not
connect more than 3 repeaters in series.
Baud 9.6 19.2
rate
(kbit/s)
Range/ 1200 m 1200 m
segment
Range in relation to transmission speed.
User Manual RWF55...
12 Profibus-DP interface
93.75 187.5 500
1200 m 1000 m 400 m
1500 12000
200 m 100 m
CC1U7867en
05.11.2013