Types Of Storage - Siemens SIMATIC S7 System Manual

If the upload is successful, you can save the uploaded program, or make further changes.
The PLC does not contain symbol or status chart information; hence, you cannot upload a
symbol table or status chart.
Note
Uploading into a new project is a risk-free way to capture the program block, system block,
and/or data block information. Since the project is empty, you cannot inadvertently destroy
data. If you want to make use of material from a status chart or symbol table that are in
another project, you can always open a second instance of STEP 7-Micro/WIN SMART and
copy that information in from the other project file (Page 111).
Uploading into an existing project is useful if you want to overwrite all modifications that have
been made to the program since it was downloaded (Page 89) to the PLC. Uploading into an
existing project does, however, overwrite any additions or modifications you have made to
the project. Use this option, only if you want to completely overwrite your
STEP 7-Micro/WIN SMART project with the project stored in the PLC.
STEP 7-Micro/WIN SMART does not upload comments, but if you currently have a program
with comments open in the program editor, the comments are retained. Take care if
uploading over an existing project and use this method only if the projects are similar.
4.3.3

Types of storage

The CPU provides a variety of features to ensure that your user program and data are
properly retained.
● Retentive memory: selectable areas of memory that remain unchanged over a power
cycle. Retentive memory can be configured in the system data block. V, M, and current
values to timers and counters are the only memory areas that can be configured to be
retentive.
● Permanent memory: memory used to store the program block, data block, system block,
forced values, as well as values configured to be retentive.
● Memory card: removable microSDHC card for standard CPUs that you can use for the
following purposes:
– To store the projects blocks as a program transfer card (Page 97)
– To completely erase the PLC as a restore-to-factory-defaults card (Page 167)
– To update the PLC and expansion module firmware as a firmware update card
S7-200 SMART
System Manual, V2.3, 07/2017, A5E03822230-AF
(Page 94)
PLC concepts
4.3 Saving and restoring data
93