Description:
The attached document contains a description of the various memory concepts. To give you a better overview, the various memory concepts in the document are described in separate tables. The last chapter of the document includes a list of the various SIMATIC S7-300 controllers and C7 devices and their associated memory concepts.

The document is divided into the following chapters:

1. Overview of the Memory Areas and Memory Concept
   1.1 Memory Areas
         1.2 Memory Concept
         1.2.1 Load Memory
         1.2.2 Main Memory
         1.2.3 System Memory
   1.3 Determining the Memory Parameters of a CPU
    
2. SIMATIC S7-300 CPUs and C7 Devices Without Bay
   2.1 Graphic Display of the Memory Concept
   2.2 Load Memory
   2.3 Main Memory
   2.4 Application of the Buffer Battery
    
3. SIMATIC S7-300 CPUs and C7 Devices With MC Bay
   3.1 Graphic Display of the Memory Concept
   3.2 Load Memory
   3.3 Main Memory
   3.4 Application of the Buffer Battery
    
4. SIMATIC S7-300 CPUs and C7 Devices With MMC Bay
   4.1 Graphic Display of the Memory Concept
   4.2 Load Memory
   4.3 Main Memory
   4.4 Application of the Buffer Battery
    
5. Memory Concepts of SIMATIC S7-300 CPU Types and C7 Device Types in Detail
   
   5.1 Memory Concepts of SIMATIC S7-300 CPU Types
   5.2 Memory Concepts of C7 Device Types

  Attachment 01: Speicherkonzepte_bei_SIMATIC_S7-300_e.pdf ( 396 KB )  

Important:
The memory concept for the SIMATIC CPU 318-2DP is similar to that for the SIMATIC S7-400 CPUs (see Entry ID:7302549).

Information on SIMATIC S7-300 CPUs with/without memory card (MC) is available in the following entries.

• Data of the individual CPUs is available in the manual "SIMATIC PLC S7-300, CPU Specifications CPU 312 IFM to CPU 318-2 DP ", section 1.4 in Entry ID: 8860591
• Notes on the various types of memory card and their properties are available in "SIMATIC PLC S7-300, CPU Specifications CPU 312 IFM to CPU 318-2 DP", section 1.1 in Entry ID: 8860591

Information on SIMATIC S7-300 CPUs with micro memory card (MMC) is available in the following entries.

• Data of the individual CPUs is available in the manual "CPU 31xC and CPU 31x: Specifications", chapters 6 and 7 in Entry ID: 12996906
• Notes on the various types of micro memory card and their properties are available in "S7-300 CPU 31xC and CPU 31x, Specifications", sections 4.1, 6.1 and 7.1 in Entry ID: 12996906
• Notes on overall reset of the CPU can be found in the manual "S7-300 CPU 31xC and CPU 31x, Specifications", section 4.2, in Entry ID: 12996906

Information independent of the type of memory card (MC or MMC)

• Notes on the topic of "How can you back up your program from the load memory?" are available in Entry ID: 299133
• Notes on the topic of "What is the effect of the STEP 7 function "Copy RAM to ROM"?" are available in Entry ID: 15389520

Keywords:
CPU selection, Memory cards