Siemens S7-1500 Function Manual page 73

SIMATIC memory card
4.4 Service life of the SIMATIC memory card
Calculation with more frequent write accesses and a higher number of bytes written
If the frequency of write accesses and the number of bytes written per day increases, the
service life of the SIMATIC memory card is reduced.
The following table shows, based on empirical values, how the service life of a SIMATIC
memory card with a size of 256 MB is reduced
Write accesses per day
50
100
400
400
400
The following table shows how the same values impact the service life of a SIMATIC
memory card with a size of 2 GB (6ES7954-8LP01-0AA0).
Write accesses per day
50
100
400
400
400
The result shows that a high number of write accesses together with a high number of
written bytes significantly shortens the service life of the SIMATIC memory card.
Reference
You can find an alternative method for calculating the service life of a SIMATIC memory card
in an FAQ on the Internet (https://support.industry.siemens.com/cs/ww/en/view/109482591).
GetSMCinfo instruction
In STEP 7 (TIA Portal) you have the option of reading out the inserted SIMATIC memory
card using the GetSMCinfo instruction. The following information can be read out with the
instruction:
● Memory size in KB
● Memory space used in KB
● Maintenance information: Previously used up portion of the service life in %
● Configured amount of the service life in % after which the CPU creates a diagnostics
buffer entry and the maintenance LED switches on.
You can find additional information on the GetSMCinfo instruction in the STEP 7 online help.
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Number of bytes written per instruction
1024000
1024000
1024000
2048000
4096000
Number of bytes written per instruction
1024000
1024000
1024000
2048000
4096000
Service life of the SIMATIC memory
card in years
287
143
36
18
9
Service life of the SIMATIC memory
card in years
1149
575
144
72
36
Structure and Use of the CPU Memory
Function Manual, 10/2018, A5E03461664-AC