In some versions, entering "CLEARPLC" as the password will wipe the memory and remove protection.
The Siemens SIMATIC S7-200 SMART is a widely used micro Programmable Logic Controller (PLC) designed for the lower performance range. As with most industrial control systems, security is a primary concern. When a password is lost or an employee leaves without documenting credentials, the machine often becomes inaccessible. This creates a demand for "password unlock" work.
The most secure level where a password is required for almost all operations, including uploading or downloading the program. Method 1: The "Factory Reset" (No Password Recovery)