Siemens SIMATIC IPC827D - Page 53

Extended device functions
5.2 Enhanced Write Filter (EWF)
SIMATIC IPC627D/827D
Operating Instructions, 09/2014, A5E32990859-AB
53
Note
The EWF commands affecting the write protection do not become active until after the next
booting process.
Note
The EWF command
ewfmgr c: -commitanddisable may not be used with the option -live
: not
ewfmgr c:
-
commitanddisable
-
live
.
Special notes for use
If EWF is enabled, when the PC shuts down all changes made on drive C: after the boot
process are lost.
These changes are only retained on the PC in the following cases:
● EWF is disabled when you make changes.
● EWF is enabled and you save the changes before shutting down the device using the
following command on C: drive :
ewfmgr c: -commit
Note
When the system is set to automatically adjust the clock for daylight saving time adjustment,
systems
without central time management and with activated EWF set the clock forward or
backward by one hour in the daylight saving time or standard time period each time the
system boots.
The reason for this behavior is that Windows
Embedded Standard 7 makes a registry entry
that the changeover to daylight saving time has occurred. Since this file is also protected
against modification by the EWF, the marker is lost during the boot sequence and the
adjustment is made again.
We therefore recommend that you deactiva
te the automatic adjustment and change the
clock manually.
Follow these steps:
1.
Deactivate automatic adjustment in the Control Panel: In the "Time Zone" tab opened
with the menu command "Start > Control Panel > Date and Time", remove the check
mark from the "Automatically adjust clock for daylight saving changes" check box.
2.
Save the change you made with
ewfmgr c:
-
commit
and then reboot the system.