Memory concept 
  4.2 Memory functions 
CPU 31xC and CPU 31x, Technical Data 
Manual, 01/2006 Edition, A5E00105475-06 
4-15 
 
 
 
Note 
As a precaution against loss of data, always make sure that you do not exceed the 
maximum number of delete/write operations. Also refer to the SIMATIC Micro Memory 
Card (MMC) section in the "Structure and Communication Connections of a CPU" 
chapter. 
 
 
 
 
Caution 
Data on a SIMATIC Micro Memory Card can be corrupted if you remove the card while it 
is being accessed by a write operation. In this case, you may have to delete the SIMATIC 
Micro Memory Card on your PG, or format the card in the CPU. Never remove a 
SIMATIC Micro Memory Card in RUN mode. Always remove it when power is off, or 
when the CPU is in STOP state, and when the PG is not writing to the card. When the 
CPU is in STOP mode and you cannot not determine whether or not a PG is writing to 
the card (e.g. load/delete block), disconnect the communication lines.