Specifications

PROFIBUS

System Overview

Topologies

2/78

Siemens LV 1 · 2007

Mixed network

Mixed structures consisting of an electrical and an optical

network are possible. The transition between the two media

is effected by an OLM.

In the way stations on the bus communicate with each other

there is no difference between two-wire technology and fiber

optic technology. Up to 127 stations can be connected to one

PROFIBUS network.

Optical transmission technology provides the following

advantages:

• Optical conductors made of plastic or glass are insensitive to

electromagnetic radiation, hence the EMC measures required

for electrical networks are superfluous

• No additional lightning protection concept is needed outdoors

• The potentials on the modules are automatically isolated

thanks to the conductor characteristics

• With optical conductors it is possible to span large distances

to field devices

Network configuration with an electrical and an optical PROFIBUS combined

OP 17

S7-300

ET 200M

ET 200S

OLM OLM OLM OLM

G_IK10_XX_50135

ET 200pro ET 200pro

ET 200S

Control cabinet

Bus cable for

PROFIBUS

Glass FOC