Siemens Automation System S7-400 - Manual (Page 139)

Commissioning
6-11
Automation System S7-400 Hardware and Installation
A5E00850741-01
6.7 Inserting a Memory Card
The Memory Card as Load Memory
You can insert a Memory Card into any S7-400 CPU. This card represents the load
memory expansion of the CPU. Depending on the type of memory card, the user
program is retained on the memory card even when power is removed.
What Type of Memory Card Should You Use?
There are two types of memory card: RAM cards and Flash cards.
Whether you use a RAM card or a Flash card depends on how you intend to use
the memory card.
If You ... ...Then
only intend to expand the integrated load
memory of the CPU,
you should 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),
you should use a Flash card.
Further information on the memory cards can be found in the CPU Manual,
Chapter 1.