: Perform a manual reset using the CPU's mode selector switch (MRES) while the MMC is removed to return the unit to its delivery state. Critical Considerations How to restore the PLC without the password? - SiePortal
: Use a tool (e.g., s7ImgRd1 ) to create a backup image of the MMC. unlock s7300exe work
: Insert the MMC into a different S7-300 CPU with a different hardware configuration. The mismatched config will trigger a memory reset request, allowing you to clear the card. : Perform a manual reset using the CPU's
To perform work involving these types of "unlock" utilities, the following hardware and software are typically required: A USB-to-MPI/DP adapter or a Field PG. : Insert the MMC into a different S7-300
: If you have the original project file, you can change protection levels in the Hardware Configuration (HW Config) under the CPU's Protection tab. Working with S7-300 Software
tool and load your MMC image. It will search the hex data to find the plain-text password (usually at a specific offset). Access the PLC