The safest way to format or reset a Siemens MMC is through official Siemens software or directly via the PLC hardware.
These community-developed tools allow you to take an "image" (.img) of a working Siemens MMC and "burn" it onto the corrupted card. siemens mmc card format tool
provides a dedicated interface for resetting and formatting cards across multiple devices at once. Select the target CPUs in the device table. Operations > Reset > Format Memory Card Critical Warnings Incompatibility: Standard SD/MMC cards purchased from electronics stores will not work The safest way to format or reset a
Even viewing it in Windows Explorer can sometimes lead to accidental corruption. Select the target CPUs in the device table
Primarily for HMI panels, but older versions (V8.2 and below) can format specific MMCs for S7-300/400. Generally not recommended for pure PLC cards.
1️⃣ You need a standard Siemens PG or a PC with a compatible PCMCIA slot (or a USB adapter). You also need the executable file (often referred to as the S7MemFormat tool).
Instead of a third-party "format tool," use the following built-in methods provided by Siemens software and hardware: 1. Hardware Reset via CPU ( Go to product viewer dialog for this item.