Siemens S7-300 appendix Memory concept Memory functions

Memory concept

4.2 Memory functions

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 MMC on your PG, or format the card in the CPU. Never remove an MMC in RUN mode. Always remove it when power is off, or when the CPU is in STOP state, and when the PG is not a 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.

4-16	CPU 31xC and CPU 31x, Technical data
	Manual, Edition 08/2004, A5E00105475-05