Protective Functions For Data Carriers - Siemens SIMATIC ET 200SP User Manual

8.5

Protective functions for data carriers

NOTICE
Data loss
The number of write cycles on CFast cards is limited due to technical reasons.
To prevent data loss, the CFast card must therefore be provided with special protection.
Use a write filter to lengthen of service life of the CFast card and avoid the
CPU 1515SP PC (F).
Write filters
Two write filters are available for Windows Embedded:
● To protect an entire partition of the CFast card, use the Enhanced Write Filter EWF
(Page 78).
Unlike FBWF, you can also use EWF with compressed NTFS data systems.
● Use the File-Based Write Filter FBWF (Page 82), to update specific files dynamically.
The FBWF can be configured more flexibly and enables direct write access without
restart.
NOTICE
Data loss
If both write filters are activated, the EWF blocks direct write access of the FBWF.
Data get lost after a restart of CPU 1515SP PC (F).
Activate only one of the two write filters per partition.
CPU 1515SP PC (F)
Manual, 05/2017, A5E32701806-AC
8.5 Protective functions for data carriers
Functions
77