Campbell NL115, Instruction Manual

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Appendix B. PC/CF Card Information
PC or CompactFlash (CF) cards provide a relatively inexpensive, off-the-shelf
means of retrieving data from many of our CRBasic dataloggers or expanding
the on-board datalogger memory. The datalogger’s memory can be expanded
up to 2 Gbytes with the use of these cards. Some dataloggers can use either a
PC or CF card, and others can only use a CF card with the appropriate
expansion module. Table B-1 lists the compatibility between dataloggers and
cards.
TABLE B-1. CRBasic Dataloggers and PC/CF Cards
Datalogger Card Slot CF Card PC Card
CR200 Not Available Not Available Not Available
CR800/850 Not Available Not Available Not Available
CR1000 CFM100 or NL115 Yes No
CR3000 CFM100 or NL115 Yes No
CR5000 Built In Yes, with Adaptor Yes
CR9000(X) Built In Yes, with Adaptor Yes
PC/CF cards use NAND (Not AND) Flash (non-volatile) memory which has
the following characteristics: high density, low cost/bit, sequential access,
scalable, and a single standard. There are two types of NAND Flash memory:
Single-Level Cell (SLC) and Multi-Level Cell (MLC). SLC NAND Flash
sometimes called Binary Flash, store one bit of data per memory cell and has
two states: erased (1) or programmed (0). MLC NAND Flash store two bits of
data per memory cell and has four states: erased (11), two thirds (10), one
third (01), or programmed (00)
1
. At first glance, the MLC cards seem more
desirable, because each cell can hold more information. However, as
summarized in Table B-2, the increased data storage comes at a price, mainly
speed.
TABLE B-2. SLC and MLC Performance Characteristics
SLC MLC
Voltage 3.3 V / 1.8 V 3.3 V
Page Size / Block Size 2KB / 128KB 512 B / 32 KB or 2 KB /
256 KB
Access Time (maximum) 25 µs 70 µs
Page Program Time 250 µs 1.2 ms
Partial Programming Yes No
Endurance 100,000 10,000
Write Data Rate 8 MB/s+ 1.5 MB/s
There is a notable performance difference between the two types of NAND
Flash memory. In a performance study by Samsung Electronics
2
, Samsung
B-1