Siemens Simatic S7-300 CPU 31xC Series Installation And Operating Instructions Manual page 164

Commissioning
8.6 Commissioning PROFINET IO
Status/control, programming via PROFINET
As an alternative to the MPI interface, you can program the CPU or execute the PG's status
and control functions via the PROFIBUS­DP interface.
If you have not commissioned the PROFINET interface of the CPU yet, you can connect to
the CPU using its MAC address (see also Configuring the PROFINET IO System in the table
above).
To do so, use HW Config to download your project to the CPU. Address the CPU using its
MAC address. After you downloaded the configuration, the CPU is also assigned the set IP
address. You can now use all PG functions at the interface, for example, Load program,
Status/Control,... .
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S7-300, CPU 31xC and CPU 31x: Installation
Operating Instructions, Edition 08/2004, A5E00105492-05