Siemens S7-300 appendix MMC copy protection, Useful life of an MMC

Memory concept

4.1 Memory areas and retentivity

MMC copy protection

Your MMC has an internal serial number that provides copy protection at user level. You can read this serial number from the SSL partial list 011CH index 8 using SFC 51 "RDSYSST." You can then program a STOP command, for example, in a copy-protected block if the expected and actual serial numbers of your MCC do not tally.

Reference

•SSL partial list in the instruction list, or

•in the manual System and Standard Functions.Information on CPU memory reset: Operating instructions CPU 31xC and CPU31x, Commissioning, Commissioning Modules, CPU Memory Reset by means of Mode Selector Switch

Useful life of an MMC

The useful life of an MMC depends mainly on following criteria:

1.The number of delete or programming operations,

2.External influences such as ambient temperature.

At ambient temperatures up to 60 °C, a maximum of 100,000 delete/write operations can be performed on an MMC.

Caution

To prevent loss of data, always make sure that you do not exceed the maximum number of delete/write operations.

See also

Operating and display elements: CPU 31xC (Page 2-1)

Operating and display elements: CPU 312, 314, 315-2 DP: (Page 2-5)

Operating and display elements: CPU 317-2 DP (Page 2-7)

Operating and display elements: CPU 31x-2 PN/DP (Page 2-9)

4-10	CPU 31xC and CPU 31x, Technical data
	Manual, Edition 08/2004, A5E00105475-05