Structure of a CPU 41x
2.8 Use of the Memory Cards
S7-400 Automation System, CPU Specifications
Manual, 10/2006, 6ES7498-8AA04-8BA0
2-19
2.8 Use of the Memory Cards
Types of Memory Cards for S7-400
Two types of memory card are used in the S7-400:
● RAM cards
● Flash cards (FEPROM cards)
Note
Parameters which determine the behavior of the CPU Non-Siemens memory cards
cannot be used in the S7-400.
Which Type of Memory Card Should Be Used?
Whether you use a RAM card or a flash card depends on how you intend to use the memory
card.
Table 2-11 Types of Memory Cards
If you ... Then ...
Want to store the data in RAM and edit your
program in RUN,
Use a RAM card
Want to store your user program permanently on
the memory card, even with power removed
(without backup or outside the CPU),
Use a Flash card
RAM card
To use a RAM card and load the user program, you must insert it into the CPU slot. The user
program is loaded with the help of the programming device (PG).
You can load the entire user program or individual elements such as FBs, FCs, OBs, DBs, or
SDBs to the load memory in when the CPU is in STOP mode or RUN.
All data on the RAM Card are lost when you remove it from the CPU. The RAM card does
not have a built-in backup battery.
If the power supply has a functioning backup battery or an external backup voltage is
supplied to the CPU via the "EXT. BATT." socket, the contents of the RAM card are retained
after power is switched off, provided the RAM card stays in the CPU and the CPU stays in
the rack.
Flash Card
You have two options of loading the user program when using a flash card:
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