Siemens SIMATIC NET PROFIBUS - Manual (Page 260)

Lightning and Surge Voltage Protection for LAN Cables Between Buildings
B-6
PROFIBUS Networks SIMATIC NET
6GK1970-5CA20-0AA1 Release 2 05/2000
B.2.2 Instructions for Installing Fine Protection
The fine protection should be installed as close as possible to the first bus node
following the coarse protection.
The following are required to install the fine protection:
S
The base section type no. 919506,
S
The protection module MD/HF type no. 919570,
and
S The shield contact terminals type no. 919508
The fine protection should be connected to the reference ground of the first bus
node (for example grounded DIN rail when installing in a cubicle). When installing
the fine protection outside cubicles (IP 65 area or higher) this must be installed in
S
protective casing, type no. 906055
as described in the installation instructions for the coarse protection.
Figure B-3 Fine Protection in the cubicle Close to the First Bus Node