Siemens SIMATIC NET PROFIBUS - Manual (Page 75)

Configuring Networks
3-9
PROFIBUS Networks SIMATIC NET
6GK1970-5CA20-0AA1 Release 2 05/2000
3.1.4 Configuring Electrical Networks with RS-485 Repeaters
RS-485 Repeater
To increase the number of nodes (>32) in a network or to extend the cable length
between two nodes, segments can be connected together using RS-485 repeaters
to form a network. Figure 3-1 illustrates how several segments can be connected
together with repeaters to create a network.
The RS-485 repeaters support all transmission rates from
9.6 Kbps to 12 Mbps.
À Terminating resistor activated
RS-485
repeater
А
А
А
А
А
ET200S
ET200M
OP 25
PG
OP 25
OP 25
S7-300
OP 25
OP 25
À
OP 25
А
А
А А
А
А
S7-300
S7-300
ET200M
ET200S
Figure 3-1 Layout of an Electrical PROFIBUS Network Using RS-485 Repeaters