Campbell CR3000 Micrologger, Руководство оператора

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Section 7. Installation
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interval that will be included in each file. For example, if the maximum file size
specified is 2 GB, the datalogger must scan through and pre-allocate 2 GB of card
memory. However, if smaller files are specified, then compile times are reduced
because the datalogger is only required to scan through enough memory to pre-
allocate memory for the smaller file.
Q: Why does a freshly formatted card cause long compile times?
A: Program compile times take longer with freshly formatted cards because the
cards use a FAT32 system (File Allocation Table with 32 table element bits) to be
compatible with PCs. Because of the way the FAT32 card format works, you can
avoid long CR3000 compile times with a freshly formatted card by first
formatting the new card on a PC, then copy a small file to the card from the PC,
and then delete the file with the PC. When the small file is copied to the card, the
PC updates a sector on the card that which allows the CR3000 program to
compile faster. This only needs to be done once when the card is formatted. If you
have the CR3000 update the card sector, the first CR3000 program compile with
the card can take as long as 30 minutes. After that, compile times will be normal.
Q: Which memory card should I use?
A: Campbell Scientific recommends and supports only the use of FMJ brand CF
cards. These cards are industrial-grade and have passed Campbell Scientific
hardware testing. Following are listed advantages these cards have over less
expensive commercial-grade cards:
•
less susceptible to failure and data loss
•
match the datalogger operating temperature range
•
faster read/write times
•
better vibration and shock resistance
•
longer life spans (more read/write cycles)
Note More CF card recommendations are presented in the application
note, CF Card Information, which is available at www.campbellsci.com.
Q: Can closed files be retrieved remotely?
A: Yes. Closed files can be retrieved using the Retrieve function in the datalogger
support software File Control
(p. 539)
utility, FTP, HTTP, or e-mail. Although open
files will appear in the CRD: drive directory, do not attempt to retrieve open files.
Doing so may corrupt the file and result in data loss. Smaller files typically
transmit more quickly and more reliably than large files.