Siemens SIMATIC NET PROFIBUS - Manual (Page 256)

Lightning and Surge Voltage Protection for LAN Cables Between Buildings
B-2
PROFIBUS Networks SIMATIC NET
6GK1970-5CA20-0AA1 Release 2 05/2000
B.1 Why Protect Your Automation System From Overvoltage?
Introduction
One of the most common causes of hardware failures is overvoltage, caused by
the following:
S
Switching in power networks
S
Atmospheric discharge or
S
Electrostatic discharge
We will show you how to protect devices attached to a PROFIBUS LAN cable from
overvoltages.
Note
This chapter contains information about protecting hardware components on a
PROFIBUS LAN cable from overvoltages.
Comprehensive protection from overvoltage is, however, only assured when the
entire automation system and the entire surrounding building is designed for
protection from overvoltages. This relates particularly to building structures
included in the planning of the building.
We therefore recommend that you contact your Siemens representative or a
company specialized in lightning protection if you require more detailed information
about overvoltage.
Further Literature
You will find detailed information about protecting automation systems from
overvoltages with SIMATIC S7 in the relevant system manuals
S7-300 /11/, S7-400 /12/, ET 200 /9/.
The solutions explained in these manuals are based on the lightning protection
zone concept described in the standard IEC 1024-2 Protection against LEMP.
B.2 Protecting LAN Cables from Lightning
Bus Cables within Buildings
If you keep to the instructions for installing LAN cables located entirely within a
building, no special lightning protection is necessary.