Technical data

Setting Up and Editing the Project
6.7 Editing a Project
Programming with STEP 7
Manual, 05/2010, A5E02789666-01 181
Accessing Data Blocks on the MMC
On the MMC, you can use data blocks and data block contents to handle larger quantities of data
or data rather scarcely required in the user program. New system operations are available for that
purpose:
• SFC 82: creating data blocks in the load memory
• SFC 83: reading from the data block in the load memory
• SFC 84: writing to a data block in the load memory
MMC and Password Protection
If a CPU (i.e. a CPU in the 300-C family) that is fitted with a Micro Memory Card (MMC) is
password-protected, then the user will also be prompted to enter this password when opening this
MMC in the SIMATIC Manager (on a programming device/PC).
Displaying Memory Assignment in STEP 7
The display of the load memory assignment in the module status dialog ("Memory" tab) shows both
the EPROM and the RAM area.
Blocks on MMCs show a 100% EPROM behavior.