Siemens SIMATIC NET PROFIBUS - Manual (Page 173)

Active Components for RS-485 Networks
5-7
PROFIBUS Networks SIMATIC NET
6GK1970-5CA20-0AA1 Release 2 05/2000
Segments 1 and 2 Terminated
Figure 5-3 shows how to connect the RS-485 repeater to the ends between two
segments:
R
Segment 1
Segment 2
Terminating resistor
Bus segment 1 Terminating resistor
Bus segment
on
Terminating resistor Terminating resistor
Bus segment 2
on
Segment 1
Segment 2
Figure 5-3 Connecting Two Bus Segments to the RS-485 Repeater
Segment 1 Terminated, Segment 2 Connected Through
Figure 5-4 shows the connection between two segments via an RS-485 repeater
with one segment connected through:
R
Segment 1
Segment 2
Terminating resistor
Bus segment 2
off! Terminating resistor
Bus segment 2
off!
Terminating resistor
Bus segment 1 Terminating resistor
Bus segment
on Terminating resistor
Bus segment 1 Terminating resistor
Bus segment
on Terminating resistor
Bus segment 1 Terminating resistor
Bus segment
on
Segment 1
Segment 2
Figure 5-4 Connecting Two Bus Segments to the RS-485 Repeater