Operating the device and device functions
5.5 Extended device functions
SIMATIC IPC677D
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Operating Instructions, 09/2014, A5E32995420-AC
5.5.1.4
Battery monitoring
The installed buffer battery has a service life of at least 5 years. The status can be checked
with two-tier battery monitoring. The information can be read from an I/O register and
evaluated.
When the first warning level is reached, the remaining service life of the battery for buffering
CMOS data and buffer memory is at least 1 month.
5.5.2
Enhanced Write Filter (EWF)
Purpose and function
The Enhanced Write Filter (EWF) is a function that is only available for Windows Embedded
operating systems. EWF is a write filter that can be configured by the user.
You can use the Enhanced Write Filter to boot Windows Embedded Standard from read-only
media, for example, memory cards or Solid State Drives (SSD), or provide individual
partitions with write protection.
EWF can be used to minimize write access to storage media. This is important because the
write cycles are limited due to technical reasons. We therefore recommend using EWF if you
work with these storage media.
If you use HORM or compressed NTFS, EWF is indispensable.
CAUTION
Data loss with several write filters
Both EWF and FBWF are preinstalled in the SIMATIC IPC images. If several writer filters
are active on one partition at the same time, you may experience data loss. This may
damage the machine or plant.
Make sure that you only activate one write filter for each partition.
Note
Windows Embedded Standard
The Enhanced Write Filter is deactivated in the Windows Embedded Standard default state.
•
Back up your data after installation of the operating system and programs.
•
Activate the EWF.
