Changing The Type Of Load Memory - Siemens SIMATIC S7-400H System Manual

System modifications in operation
14.8 Changing the CPU memory configuration
Procedure
Do the following in the sequence given:
Step What has to be done?
1 Switch the standby CPU to STOP using the PG.
2 Replace the memory card in the CPU with a card
which has a higher capacity as required.
3 Reset the standby CPU using the PG.
4 Start the standby CPU with the menu command
"PLC > Mode > Switch to CPU ... with expanded
memory configuration".
5 Turn off power to the second CPU.
6 Modify the memory configuration of the second CPU
as you did in steps 2 to 3 for the first CPU.
7 Start the second CPU from the PG.
14.8.3

Changing the type of load memory

The following types of memory cards are available for load memory:
● RAM card for the test and commissioning phase
● FLASH card for permanent storage of the completed user program
The size of the new memory card is irrelevant here.
If you change your memory configuration in this way, the system does not transfer any
program elements from the master CPU to the standby CPU. Instead, it transfers only the
contents of the unchanged blocks of the user program (see section Switch to CPU with
modified configuration or expanded memory configuration (Page 103)).
It is the user's responsibility to download the entire user program to the new load memory.
Starting situation
The fault-tolerant system is operating in redundant mode.
The current status of the user program is available on the PG/ES as a STEP 7 project in
block format.
You can not deploy a user program you uploaded from the PLC here.
It is not permissible to recompile the user program from an STL source file, because this
action would set a new time stamp at all blocks and so prevent the block contents from
being copied when you change over the master/standby station.
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CAUTION
How does the system react?
The system is now operating in single mode.
Standby CPU requests memory reset.
–
The standby CPU links up, is updated and
•
becomes the master.
Previous master CPU changes to STOP.
•
System operates in single mode.
•
The subsystem is disabled.
–
The second CPU is linked up and updated.
•
The system is now operating again in redundant
•
mode.
System Manual, 09/2007, A5E00267695-03
S7-400H