Automation and Drives - SCE
2.2MEMORY AREAS OF THE CPU 31XC
Introduction
The memory of the CPU 31xC can be divided into three areas:
Note
Only with the MMC plugged in is it possible to load user programs and therefore operate the CPU 31xC
Load memory
The load memory is located on a SIMATIC Micro Memory Card (MMC).
Its size is exactly the same as that of the MMC. It is used for storing code blocks and data blocks as well as system data (configuration, connections, module parameters, etc.).
Blocks that are marked as not being relevant to program execution are exclusively stored in the load memory.
In addition, the complete planning data for a project can be stored on the MMC.
RAM
The RAM is integrated on the CPU and cannot be expanded. It is used for processing the code and processing the data of the user program. The program is executed exclusively in the RAM and the system memory.
Once the MMC has been plugged in, the RAM of the CPU is retentive.
System memory
The system memory is integrated on the CPU and cannot be expanded.
It contains
-the operands area for clock memories, timers and counters
-the process images of the inputs and outputs
-the local data
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Foreword | Notes | Hardware configuration | STEP 7 program | Testing |
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T I A Training Document |
| Page 9 of 25 |
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| A5 | |
Issue date: 02/2008 |
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| Programming the CPU | ||
