Siemens SIMATIC NET PROFIBUS OBT, Manual

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Network Topology
4-3
PROFIBUS Optical Bus Terminal (OBT)
C79000-G8976-C122-03
4.3 Attaching RS-485 Segments
The OBT allows the attachment of a PROFIBUS - RS 485 - segment.
1) PROFIBUS cable
(terminated at both ends)
2) PROFIBUS cable
3) PROFIBUS connector (not terminated)
4) Plastic FO or PCF FO with two fibers
ET 200M without
FO interface
DP node without
FO interface
SIMATIC S7-400
with IM 467 ET 200M without
FO interface
À
Terminating resistor activted
2)
2)
2)
3)
4)
4)
1)
1)
OBT
OBT
OBT
À
À
À
À
À
À
3)
Figure 4-2 Example of Attaching RS-485 Segments