What or error messages are showing on your PLC?
Insert the MMC into the dedicated Simatic Card slot on your PG or USB Prommer. Open or TIA Portal . siemens mmc card format tool
I can provide the specific step-by-step recovery workflow for your equipment. Share public link What or error messages are showing on your PLC
Formatting should be a last resort. Here are best practices to keep your MMCs healthy: I can provide the specific step-by-step recovery workflow
Siemens Micro Memory Cards (MMCs) are specialized storage units used in SIMATIC S7-300 and ET200 manual controllers. Unlike standard commercial SD or MMC cards, these industrial cards use a proprietary internal file system. If you attempt to format a Siemens MMC using standard Windows formatting tools, you will corrupt the card's internal firmware structure, rendering it completely unreadable by a Siemens Programmable Logic Controller (PLC).
Siemens provides several official (and safest) methods for handling MMC cards. These should always be your first choice.
Right-click and select , or select Format from the S7 Memory Card menu. Step-by-Step for TIA Portal: Insert the card into your PG/Prommer. In TIA Portal, look at the left-hand Project Tree. Expand the Card Reader/USB memory directory. Locate your specific MMC slot. Right-click the memory card icon and select Format . Tool 2: The PLC "MRES" Hardware Reset Method
