Siemens SIMATIC ET 200AL System Manual page 1012

Further information about the "User router" setting
You have the possibility to configure the use of a router including IP address of the router in
the "IP protocol" section of the settings for the PROFINET interface (Ethernet addresses).
Rules
Observe the following rules if you want to configure a router for the PROFINET interface of
an IO controller:
● A PROFINET IO device supports exactly one router, irrespective of the number of
interfaces.
● You can configure a router for exactly one PROFINET interface. All IO devices that are
assigned to the PROFINET interface adopt the configured router from the IO controller.
● You cannot configure a router for the further PROFINET interfaces of the CPU. The
further PROFINET interfaces take on the IP address "0.0.0.0" as the router and pass it on
to their IO devices.
As of STEP 7 V15, you can configure the use of a router for an IO device. This allows the
IO device to communicate with a node outside its own IP subnet, irrespective of the setting
of the PROFINET interface of the IO controller.
PROFINET with STEP 7 V15
Function Manual, 12/2017, A5E03444486-AH
Parameter assignment/addressing
3.4 Specifying the router for a PROFINET IO device
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