Commissioning
7.9 Notes on operation
SIMATIC HMI IPC677C
Operating Instructions, 04/2013, A5E02722710-04
75
7.9.5
Compact Flash card (optional)
Note
We highly recommend that use use approved SIMATIC Compact Flash cards. Siemens
disclaims any liability for impairment of functions caused by the use of third-party cards.
Design
A Compact Flash card can be used on-board and in an extra mount. This mount replaces the
usual hard disk mount.
Characteristics
The Flash drive with Compact Flash card reacts just like any standard IDE hard disk preset
as a master. No special driver software is required to operate the Flash drive.
Even though the Flash drive reacts like a hard disk on the outside, there are restrictions due
to the limited number of write cycles on Flash memory. The service life of a Compact Flash
card depends on the number of write access to the medium - read accesses have no effect.
To maximize the service life of Compact Flash cards, take care that the writing to the cards
is kept to a minimum.
For example, you can do this by ensuring that:
●
Swap files of the operating system and application are not located on the Compact Flash
card.
●
Cyclic writing is avoided.
Operating systems such as MS-DOS and Windows XP Embedded allow this, for example.
The Enhanced Write Filter (EWF) can be used with Windows XP Embedded, for example.
This minimizes the number of write accesses to the Flash drive or avoids it entirely.
Flash drive functions
A Flash drive or a Compact Flash card consists of Flash memory chips.
An intelligent controller integrated in the Flash drive manages the Flash memory. This
optimizes the use of the Flash memory to achieve a maximum service life.
The service life of a Flash drive depends in part on the following factors:
●
Type of file
Executable files (*.EXE) are usually only written once and stays at the same storage
location.
●
The number of writes within a given time (the less the better)
