Reference
Additional information about the memory structure and the basic meaning of these memory
areas can be found in the Function Manual Structure and Use of the CPU Memory
(https://support.automation.siemens.com/WW/view/en/59193101/0/en). This documentation
also describes how you obtain information about the memory utilization using STEP 7.
3.4.2.2
Storage of retentive data
Introduction
The CPU offers the option to store data retentively in the integrated NVRAM during
shutdown and power failure. The following data is saved:
● The current data from data blocks, bit memory, timers, counters and technology objects
that is marked as retentive in the TIA Portal
● Contents of the diagnostics buffer
● Contents of the message buffer
● Current operating mode (RUN/STOP)
The retentive data is stored automatically in the following situations:
● Shut down the CPU using command-line commands
● Power failure (by using a UPS or NVRAM)
Storage in NVRAM
The storage of retentive data in NVRAM protects you from losing important program data
after a power failure. The storage in NVRAM has the advantage that the storage process is
also possible in case of a sudden power failure. But the storage process with this method
depends on the buffer capacity of the power supply of your PC. This reduces the amount of
retentive data that can be saved compared to when saving in the mass storage.
3.4.3
Interface types
The PC has a PROFINET onboard interface. Isochronous data exchange via Isochronous
Real Time (IRT) is possible.
Additional information on the interfaces of the PC used is available in the technical
specifications for your device.
CPU 1505SP (F) Ready4Linux Version 2.7
Operating Instructions, 05/2019, A5E46864285-AA
Product overview
3.4 Functions
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