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4 ungrounded operation of the rs-485 repeater – Siemens SIMATIC NET PROFIBUS User Manual

Page 178

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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.

Figure 5-8 shows the change in the potentials resulting from using the RS 485
repeater.

Signals
ungrounded

Signals grounded

Figure 5-8

Ungrounded Operation of Bus Segments