Technical data

Topologies of SIMATIC NET PROFIBUS networks

2.2 Topologies of optical networks

PROFIBUS Network Manual

System Manual, Edition 04/2009, C79000-G8976-C124-03

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ET 200M with

IM 153-2 FO

S7 400 with

IM 467 FO

Further nodes

Line length between

2 nodes:

Plastic FOC up to 50

PCF FOC up to 300 m

OP 25

S7 300

OBT

222 11

① Terminating resistor activated

1 Fiber-optic cables

2 PROFIBUS bus cable

Figure 2-2 PROFIBUS DP network - nodes with integrated FO interfaces

For short distances, the preassembled 8301T or 8302 connecting cables can be used as an

alternative to the PROFIBUS cable.

Transmission speed

An optical PROFIBUS network with a bus topology can be operated at the following

transmission speeds:

9.6 kbps, 19.2 kbps, 45.45 kbps, 93.75 kbps, 187.5 kbps, 500 kbps, 1.5 Mbps and 12 Mbps

PROFIBUS Optical Bus Terminal (OBT)

Using a PROFIBUS optical bus terminal (OBT), an individual PROFIBUS node without an

integrated FO port or a PROFIBUS RS485 segment can be attached to the optical

PROFIBUS network (see Figure 2-2).

The attachment is made to the RS485 interface of the OBT using a PROFIBUS cable or a

preassembled connecting cable. The OBT is included in the optical PROFIBUS bus via the

FO interface.

2.2.3 Topologies with OLMs

OLMs

The OLMs have a floating electrical channel (similar to the channels on a repeater) and

depending on the version, they have one or two optical channels.

The OLMs are suitable for transmission rates of 9.6 kbps to 12 Mbps. The transmission rate

is detected automatically.