To reset the IP address of a Siemens S7-1200 or S7-1500 PLC, you can use the “Reset to factory settings” function in STEP 7 (TIA Portal). The IP address of your S7-1200/S7-1500 CPU must be identical to the IP address used in your STEP 7 (TIA Portal) project. Otherwise, no online connection is possible.
Change the IP address for your CPU in STEP 7 (TIA Portal)
In the Project tree you select the CPU.
Select the menu command “Online > Accessible devices”.
Select the settings for the PG/PC interface and click “Start search”.
The IP address of your CPU is displayed in the “Address” column.
Open the properties of the CPU.
In the “General” tab you navigate to “PROFINET interface [X1] > Ethernet addresses”.
In the “IP address:” field you enter the IP address of your CPU.
Reset the IP address of the S7-1500 CPU to factory settings
Make sure that there is no SIMATIC MC memory card in your CPU when deleting the IP address.
In the project navigation you mark the CPU and select the menu command “Go online”.
In the project navigation you select “Online & Diagnostics”.
In the “Online access” dialog you navigate to “Functions > Reset to factory settings”.
Enable the “Delete IP address” option.
Click the “Reset” button.
You will be asked whether you really want to reset the module. Confirm with “Yes”.