Siemens S7-1500 Function Manual page 32

Diagnostics buffer
The 500 most recent entries in the diagnostics buffer are retained after power failure and are
not affected by a memory reset. The diagnostics buffer can be cleared only by a reset to
factory settings. The entries in the diagnostics buffer do not occupy any memory space in the
retentive memory.
Operating hours counter
The operating hours counters of the CPUs are retentive and are not affected by a memory
reset. By resetting to factory settings, the operating hours counters are set to zero.
Clock time
The clock time of the CPUs is retentive and is not affected by a memory reset. By resetting
to factory settings, the clock time is reset.
Reference
You can find additional information on the memory reset and reset to factory settings
functions in the following manuals:
● System manual S7-1500, ET 200MP Automation System
(http://support.automation.siemens.com/WW/view/en/59191792)
● System manual ET 200SP Distributed I/O System
(http://support.automation.siemens.com/WW/view/en/58649293)
● Operating instructions ET 200pro CPU 1516pro-2 PN
(https://support.industry.siemens.com/cs/ww/en/view/109482416)
● System manual Redundant System S7-1500R/H
(https://support.industry.siemens.com/cs/ww/en/view/109754833)
Structure and Use of the CPU Memory
Function Manual, 10/2018, A5E03461664-AC
Memory areas and retentive memory
2.4 Summary of retentive behavior
31