C-20 – Siemens SIMATIC NET PROFIBUS User Manual

Page 282

Installing LAN Cables

C-20

PROFIBUS Networks SIMATIC NET

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

C.6

Electromagnetic Compatibility of Fiber-Optic Cables

Fiber-Optic Cables

For LAN cables between buildings and/or external facilities, the use of fiber-optic
cables is generally recommended. Due to the optical transmission principle,
fiber-optic cables are not affected by electromagnetic interference. Measures for
equipotential bonding and for overvoltage protection are unnecessary with
fiber-optic cables.

Note

Fiber-optic cables are ideally suited for LAN connections in areas with high noise
levels.

Remember, however, that the LAN components operating on an electrical basis
such as OLMs, OBTs or PLCs with integrated optical interfaces may require
additional noise protection measures in such areas before they can be included in
the fiber–optic path. These must be protected using the measures already
mentioned such as shielding, grounding, greater clearance to sources of
interference etc.