Siemens SIMATIC PROFINET Function Manual page 53

Identification of the PROFINET device
To clearly identify a device from several identical devices in a control cabinet, for example,
you can flash the link LED of the PROFINET device.
To do this, select the menu command Online > Accessible devices... in STEP 7. In the
"Accessible devices" dialog, set the "PG/PC" interface by means of which you are connected
to the devices. STEP 7 now automatically searches for the accessible devices and displays
them in the "Accessible devices in target subnet" table. Select the desired PROFINET device
and click on the "Flash LED" button. The PROFINET device is identified based on its MAC
address.
Figure 3-7 "Accessible devices" dialog
Using an different way to assign IP addresses for IO devices
Various IO devices, for example, SCALANCE X,S7-300 CPs, support the option of not
having the IP addresses assigned by the IO controller during startup. In this case, the IP
address is assigned in a different way. For additional information, refer to the manual of the
respective PROFINET device of the SIMATIC device family.
PROFINET with STEP 7 V14
Function Manual, 09/2016, A5E03444486-AG
Parameter assignment/addressing
3.2 Device name and IP address
53