Siemens SIMATIC NET PROFIBUS - Manual (Page 264)

Installing LAN Cables
C-2
PROFIBUS Networks SIMATIC NET
6GK1970-5CA20-0AA1 Release 2 05/2000
C.1 LAN Cables in Automation Systems
LAN Cables as Important Plant Connections
In automation systems, the LAN cables are the most important connections
between individual plant components. Mechanical damage (cable break) or
repeated electrical interference affecting these bus connections reduces the
transmission capacity of the system. In extreme cases, such problems can lead to
failure of the entire automation system. This section explains how to protect cables
from mechanical and electrical impairment.
Keep the Overall System Concept in Mind
LAN cables connect automation systems that in turn are connected to transducers,
power supply units, peripheral devices etc. via cables. All the components together
form an electrically networked automation system.
When connecting system components via electrical cables (in this case LAN
cables), remember to take into account their specific requirements in terms of
system structure.
Connecting cables, in particular, affect the concepts
S for safe isolation of dangerous power supply voltages
S
for protecting the system from overvoltage (for example lightning protection)
S
for EMC (noise emission and noise immunity)
S
for electrical isolation
Networking SIMATIC with SIMATIC NET
SIMATIC NET network components and SIMATIC automation components are
designed to operate together taking into account the aspects listed above. By
keeping to the installation instructions described in the system manuals, you will
create an automation system that meets the legal and normal industrial
requirements for safety and noise immunity.