315-4PN33

7 Deployment Ethernet communication - productive
7.1 Basics - Industrial Ethernet in automation
The flow of information in a company presents a vast spectrum of
requirements that must be met by the communication systems.
Depending on the area of business the bus system or LAN must sup-
port a different number of users, different volumes of data must be
transferred and the intervals between transfers may vary, etc. It is for
this reason that different bus systems are employed depending on the
respective task. These may be subdivided into different classes. The
following model depicts the relationship between the different bus
systems and the hierarchical structures of a company:
Industrial Ethernet is an electrical net based on shielded twisted pair
cabling or optical net based on optical fibre. Industrial Ethernet is
defined by the international standard IEEE 802.3
The net access of Industrial Ethernet corresponds to IEEE 802.3 -
CSMA/CD (Carrier Sense Multiple Access/Collision Detection)
scheme:
n Every station "listens” on the bus cable and receives communica-
tion messages that are addressed to it.
n Stations will only initiate a transmission when the line is unoccu-
pied.
n In the event that two participants should start transmitting simulta-
neously, they will detect this and stop transmitting to restart after a
random delay time has expired.
n Using switches there is the possibility for communication without
collisions.
Overview
Industrial Ethernet
VIPA System 300S Deployment Ethernet communication - productive
Basics - Industrial Ethernet in automation
HB140 | CPU | 315-4PN33 | GB | 14-43 107