6
Electrical installation
Connection of PROFINET IO
Manual – PROFINET IO Interfaces, Field Distributors
67
6.8.1
The integrated Ethernet switch
You can use the integrated Ethernet switch to achieve line topologies known from the
fieldbus technology. Other bus topologies, such as star or tree, are also possible.
INFORMATION
The number of Industrial Ethernet switches connected in line affects the telegram
runtime. If a telegram passes through the devices, the telegram runtime is delayed by
the store & forward function of the Ethernet switch:
This means the more devices a telegram has to pass through, the higher the tele-
gram runtime is.
•
For a telegram length of 64 bytes by approximately 10 µs (at 100 Mbit/s)
•
For a telegram length of 1500 bytes by approximately 130 µs (at 100 Mbit/s)
Auto-crossing
The two ports leading out of the Ethernet switch have auto-crossing functionality. This
means that they can use both patch and cross-over cables to connect to the next Eth-
ernet node.
Auto-negotiation
The baud rate and duplex mode are negotiated by both Ethernet nodes when estab-
lishing the connection. For this purpose, both Ethernet ports of the Ethernet connec-
tion support an auto-negotiation functionality and work with a baud rate of either 100
Mbit or 10 Mbit in full duplex or half-duplex mode.
22870857/EN – 12/2016
