S7-200 Password Unlock - Siemens

Specific strings whispered in automation forums include:

In the early 2000s, Siemens quietly implemented a "service password" for certain S7-200 firmware revisions. Technically known as the PPI Master Password , this backdoor allowed Siemens field service engineers to bypass forgotten passwords without a full reset. Siemens S7-200 Password Unlock

If you have forgotten the password and simply need to reuse the PLC (and do not care about the existing program), you can perform a factory reset. This deletes the program, data, and password. Connect your PC to the PLC using a PPI Multi-Master Cable STEP 7-Micro/WIN menu and select to wipe the memory. Specific strings whispered in automation forums include: In