Instead of "unlock" techniques, search for:
If the PLC protection level was set to "Read Access" or "HMI Access" (and not "No Access"), you might still be able to perform a factory reset via the software. TIA Portal: Password Protection!
Wait for the blinking to stop. the CPU and remove the card .
Please note that these methods may vary depending on the specific firmware version and configuration of your S7-1200. If you're unsure or uncomfortable with the process, it's recommended to consult the official Siemens documentation or contact a qualified automation expert.
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