Siemens SIMATIC ET 200AL System Manual page 1597

Description
2.2 Setting up PROFINET
Switches
Switches are network components used to connect several terminal devices or network
segments in a local network (LAN).
For the communication of a device with several other devices on PROFINET, the device is
connected to the port of a switch. Other communication devices (including switches) can
then be connected to the other ports of the switch. The connection between a
communication device and the switch is a point-to-point connection.
A switch has the task of receiving and distributing frames. The switch "learns" the Ethernet
address(es) of a connected PROFINET device or additional switches and only forwards those
frames that are intended for the connected PROFINET device or the connected switch.
Switch variants
Switches are available in two models:
• Integrated into a PROFINET device
For PROFINET devices with multiple ports (two or more), we are dealing with devices with
an integrated switch (for example, CPU 1516-3 PN/DP).
• As autonomous device (for example, switches of the SCALANCE product family)
Selection Guide for Switches
To use PROFINET with the RT class "RT", you can use any switch of "PROFINET Conformance
Class A" or higher. All switches of the SCALANCE product family meet these requirements.
If you want to use PROFINET functions that provide an additional value, such as topology
recognition, diagnostics, device exchange without exchangeable medium/programming
device, you have to use a switch of the "PROFINET Conformance Class B" or higher.
To use PROFINET with the RT class "IRT", you must use a switch of "PROFINET Conformance
Class C". With switches of the SCALANCE product family, watch out for the catalog feature
"IRT PROFINET IO switch".
To select appropriate switches, we recommend the SIMATIC NET Selection Tool on the
Internet (http://support.automation.siemens.com/WW/view/en/39134641).
Switches of the SCALANCE product family
Use the switches of the SCALANCE product family if you want to use the full scope of
PROFINET. They are optimized for use in PROFINET IO.
In the SCALANCE X device family, you will find switches with electrical and optical ports and
with a combination of both variants. SCALANCE X202-2IRT, for example, has two electrical
ports and two optical ports and supports IRT communication.
Beginning with the SCALANCE X200, you can configure, diagnose and address switches of
the SCALANCE X device series as PROFINET IO devices using STEP 7.
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PROFINET with STEP 7
Function Manual, 05/2021, A5E03444486-AL