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5 grounding – Siemens SIMATIC NET PROFIBUS User Manual

Page 156

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Passive Components for RS-485 Networks

4-58

PROFIBUS Networks SIMATIC NET

6GK1970-5CA20-0AA1 Release 2 05/2000

4.7.5

Grounding

If the bus terminal is mounted on a DIN rail (see Figure 4-33), the shield clamp
makes large-area contact with the rail via an internal spring. To connect the cable
shield with local ground, a connection between the DIN rail over as short a
distance as possible to local earth is adequate.

PE

A B

A

B

PE

УУУУ

УУУУ

P

E

A B

A B

P

E

УУУУУ

УУУУУ

A B

A B

PE

УУУУУ

УУУУУ

С

С

PE

A B

A B

PE

УУУУУ

УУУУУ

С

С

СС

СС

С

С

С

С

С

С

Wall installation with securing
screws

Installation with a standard rail
on a cabinet panel

Shield clamp/

PE

grounding bar

Installation on closet panel
with securing screws

Bus

terminated

Bus

terminated

Bus

terminated

Bus

terminated

Shield clamp/

grounding bar

MADE IN GERMANY

MADE IN GERMANY

MADE IN GERMANY

MADE IN GERMANY

1)

2
)

1) If this grounding cable exceeds a length of 20 cm,
the shield must be grounded to the closet panel (2).

Figure 4-33

Ways of Installing and Grounding the Bus Terminal

Note

The grounding bar and local ground must be connected by a Cu conductor with

6 mm

2

cross-section over as short a distance as possible.