Campbell Scientific CR3000 CR3000 Micrologger - Page 340
CRD: Drive
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Section 8. Operation 8.3.1.1.5 CRD: Drive 340 CRD: drive uses CompactFlash® (CF) memory cards exclusively. Its primary purpose is the storage of binary data files. See File-System Errors (p. 352) for explanation of error codes associated with CRD: use. Caution When installing or removing card-storage modules, first turn off CR3000 power. Removing a card from the module while the CF card is active can cause data corruption and may damage the card. Always press the removal button to disable the card and wait for the green LED before removing the card or switching off power prior to removal of the card. To prevent losing data, collect data from the CF card before sending a program to the datalogger. When a program is sent to the datalogger all data on the CF card may be erased. Campbell Scientific CF card modules connect to the CR3000 peripheral port. Each has a slot for Type I or Type II CF cards. A maximum of 30 data tables can be created on a CF card. Refer to Writing High-Frequency Data to CF Cards (p. 273) for information on programming the CR3000 to use CF cards. Refer to the appendix Card-Storage Modules for information on available CF-card modules. Note CardConvert software, included with mid- and top-level datalogger support software (p. 404, p. 453), converts binary card data to the standard Campbell Scientific data format. When a data table is sent to a CF card, a data table of the same name in SRAM is used as a buffer for transferring data to the card. When the card is present, the Status table will show the size of the table on the card. If the card is removed, the size of the table in SRAM is shown. When a new program is compiled that sends data to the CF card, the CR3000 checks if a card is present and if the card has adequate space for the data tables. If no card is present, or if space is inadequate, the CR3000 will warn that the card is not being used. However, the user program runs anyway and data are stored to SRAM. When a card is inserted later, data accumulated in the SRAM table are copied to the CF card. Formatting CF Cards The CR3000 accepts cards formatted as FAT or FAT32; however, FAT32 is recommended. Otherwise, some functionality, such as the ability to manage large numbers of files (>254) is lost. Older CR3000 operating systems formatted cards as FAT or FAT32. Newer operating systems always format cards as FAT32. To save time, use a PC to format CF cards. After formatting the card, write any file to the card, then delete the file. This action sets up the card for faster initial use. FAT32 uses an "info sector" to store the free cluster information. This info sector prevents the need to repeatedly traverse the FAT for the bytes free information. After a card is formatted by a PC, the info sector is not automatically updated. Therefore, when the datalogger boots up, it must determine the bytes available on the card prior to loading the Status table. Traversing the entire FAT of a 16 GB card can take up to 30 minutes or more. However, subsequent compile times are much shorter because the info sector is used to update the bytes free information. To avoid long compile times on a freshly formatted card, format the card on a PC,