Siemens SIMATIC NET PROFIBUS manual Why Protect Your Automation System From Overvoltage?

Lightning and Surge Voltage Protection for LAN Cables Between Buildings

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:

SSwitching in power networks

SAtmospheric discharge or

SElectrostatic 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.

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