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STEP 7 Operations and Components
5.4
Loading and Storing the STEP 7 User Program
5.4.1
Load and Work Memory, Memory Card File
Load and Work Memory
When you load the STEP 7 user program to the CPU 41x-2 PCI, the code and data
blocks are loaded to the load memory and work memory areas of the CPU 41x-2
PCI.
To ensure rapid processing of the STEP 7 user program, only those parts of the
blocks that are relevant for program execution are loaded onto the work memory
area. Block parts that are not required for program execution (e.g., block headers)
remain in the load memory area.
The following diagram illustrates loading of the program to the CPU memory:
Structure of the Load Memory
The load memory can be expanded through use of a memory card. Depending on
whether you select a RAM card or a FLASH card for expanding the load memory,
the behavior during loading, reloading, and resetting can differ. For more
information on this topic, refer to Types of Memory Cards.
Definition
A memory card file represents the content of the memory card. The memory card
file contains the STEP 7 user program and the hardware configuration (SDBs).
•
If you use STEP 7 to create the memory card file, the DBs will contain the
initial values.
•
If you use the controller panel to create the memory card file with File >
Archive CPU, the DBs will contain the current values.
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Hardware Installation and Operating Manual, Edition 02/2006, A5E00273194-02
Windows Automation Center, WinAC Slot Version 4.0
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