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Building Technologies Division
User Manual RWF55...
CC1U7867en
Infrastructure & Cities Sector
12 Profibus-DP interface
05.11.2013
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
rate
(kbit/s)
9.6 19.2 93.75
187.5
500 1500
12000
Range/
segment
1200 m
1200 m
1200 m
1000 m
400 m
200 m
100 m
Range in relation to transmission speed.
Basic features
Structure
Cable length