Casella CEL Sensus data logger unit - Manual (Page 28)

7. COMPACTFLASH ™ CARDS
CompactFlash memory cards are
lightweight, small form factor,
removable data storage devices
built around reliable Flash storage
technology.
The Sensus Logger’s
integrated CompactFlash slot
allows it’s storage capacity to be
increased and in addition provides
a compact and reliable method of
transporting data from site for
analysis. The slot is located on the
right-hand side of the unit directly
above the primary RS 232 9-way D-Type port as shown in Figure 20.
The unit has been designed to recognise CompactFlash ATA cards
and treat them as IDE hard disk drives, thereby simplifying the process of
data transfer to PCs. The same card can be connected to a suitably equipped
PC and the files transferred without the need for specialist software.
The current technical specification for suitable CompactFlashTM
cards is outlined below.
Operating voltage 3.3 V DC
Temperature range -20 to +70 o C
Physical size CompactFlash CF Type 1
Capacity 4 MB to 256 MB
Note: capacity is limited by file system,
only FAT12 and FAT16 are supported.
A card can hold data from only one logger at any time, irrespective of the
capacity of the card or the amount of data it holds. When a logger writes data
to the card, it also writes an electronic signature uniquely identifying this
logger. From then on (or until the card is erased) the card can be used only
with this particular logger.
The electronic signature also identifies the logger configuration used
to create any data on the card. If the configuration has changed since the
card was last used, then the signature will not be accepted as this could
result in a misinterpretation of the stored data later on. This ensures the
integrity of the data until off-loaded to a PC.
Before use, all cards must be formatted on a suitable PC.
The logger automatically checks the type of card, signature and
configuration every time a new card is inserted. The correct orientation for
inserting the card is shown in Figure 21.
Having accepted the card as suitable for data storage, the logger
transfers any stored data to the card. In addition while the card remains
inserted all new data will be logged to the card, rather than stored internally.
The card can be removed any time the logger is not actively writing
new data to it. During these periods, the LCD shows a card busy message
and the card should not be removed.
CompactFlash Cards
Figure 20: The CompactFlash slot and
RS 232 Command port
Page 28 of 44
SENSUS Digital Data Logger -
Users Handbook