Technical data

Setting Up and Editing the Project
6.7 Editing a Project
Programming with STEP 7
180 Manual, 05/2010, A5E02789666-01
6.7.3 Micro Memory Card (MMC) as a Data Carrier
6.7.3.1 What You Should Know About Micro Memory Cards (MMC)
Micro Memory Cards (MMC) are plug-in memory cards, for example, for a CPU 31xC or an
IM 151/CPU (ET 200S). Their most distinguishing feature is the highly compact design.
A new memory concept has been introduced for MMCs. It is briefly described below.
Content of the MMCs
The MMC serves as both the load memory and a data storage device (data carrier).
MMC as Load Memory
The MMCs contain the complete load memory for an MMC-compatible CPU. The load memory
contains the program with the blocks (OBs, DBs, FCs, ...) as well as the hardware configuration.
The contents of the load memory influence the functioning of the CPU. In the MMC's function as
load memory, blocks and the hardware configuration with loading functions can be transferred from
it (i.e. Download to CPU). Blocks downloaded to the CPU take effect immediately; however, the
hardware configuration does so only after the CPU is restarted.
Response to Memory Reset
The blocks stored on the MMC are retained after a memory reset.
Loading and Deleting
You can overwrite the blocks on the MMC.
You can erase the blocks on the MMC.
You cannot restore overwritten or erased blocks.