Siemens SIMATIC S7-400 Manual page 32

Structure of a CPU 41x
2.8 Use of the Memory Cards
Option 1:
1. Set the CPU mode switch to the STOP state with the mode selector switch.
2. Insert the flash card into the CPU.
3. Perform a memory reset.
4. Load the user program with the STEP 7 command "PLC -> Download User Program to
Option 2:
1. Load the user program to the flash card when the programming device / programming
2. Insert the flash card into the CPU.
You can only reload the full user program using the Flash card. You can load smaller
program sections into the integrated load memory on the CPU using the programming
device. In the case of extensive program changes, you must always reload the Flash card
with the full user program.
The Flash card does not require a backup voltage, that is, the information stored on it is
retained even when you remove the Flash card from the CPU or if you operate your S7-400
system without a buffering function (without backup battery in the power supply module or
"EXT. BATT." socket of the CPU).
Which Memory Card Capacity Should Be Used?
The capacity of the required memory card is based on the size of the user program and
amount of system data.
To optimize utilization of work memory (code and data) on your CPU, you should expand the
load memory of the CPU with a memory card which has at least the same capacity as the
work memory.
Changing the Memory Card
To change the memory card:
1. Set the CPU to STOP.
2. Remove the memory card.
3. Insert the "new" memory card in the CPU.
4. Reset the CPU memory.
2-20
Memory Card".
adapter is offline.
Note
If you remove the memory card, the CPU requests a memory reset in a 3-sec sequence,
which is indicated by the flashing STOP LED. This sequence cannot be influenced by
error OBs.
S7-400 Automation System, CPU Specifications
Manual, 10/2006, 6ES7498-8AA04-8BA0