Siemens SIMATIC NET PROFIBUS User Manual
Active Components for RS-485 Networks
5-12
PROFIBUS Networks SIMATIC NET
6GK1970-5CA20-0AA1 Release 2 05/2000
5.4
Ungrounded Operation of the RS-485 Repeater
Ungrounded Operation
Ungrounded operation means that chassis and PE are not connected.
The ungrounded operation of the RS-485 repeater allows you to operate
electrically isolated bus segments.
electrically isolated bus segments.
Figure 5-8 shows the change in the potentials resulting from using the RS 485
repeater.
repeater.
Signals
ungrounded
ungrounded
Signals grounded
Figure 5-8
Ungrounded Operation of Bus Segments