MicroSD (CRD: drive)
The data logger has a microSD card slot for removable, supplemental memory. The card can be configured as an extension of the data logger final-data memory or as a repository of discrete data files.
When storing high-frequency data, or when storing data to cards greater than 2 GB, TableFile() with Option 64 is recommended to write final storage data to a card. In other applications CardOut() can be used to store data to a card.
Sub-folders are not supported.
See the CRBasic Editor help for detailed instruction information and program examples: 
The CRD: drive uses microSD cards exclusively. Campbell Scientific recommends and supports only the use of microSD cards obtained from Campbell Scientific. These cards are industrial-grade and have passed Campbell Scientific hardware testing. Use of consumer-grade cards substantially increases the risk of data loss. Following are advantages Campbell Scientific cards have over less expensive commercial-grade cards:
- Verified compatibility with Campbell Scientific data loggers
- Less susceptible to failure and data loss
- Match the data logger operating temperature range
- Provide faster read/write times
- Include vibration and shock resistance
- Have longer life spans (more read/write cycles)
A "card controller error" indicates that the data logger has failed to communicate with the card. It is an error caused by the micro-controller built into the microSD card. Sometimes this error may be resolved by reformatting the card. If the error repeats itself, try an industrial-grade card. For more information on errors, see File system error codes.
A maximum of 30 data tables can be created using CardOut() on a microSD card. When a data table is sent to a microSD card, a data table of the same name in SRAM is used as a buffer for transferring data to the card. Note that with TableFile(), the number of files stored on the card is controlled by the MaxFiles parameter.
When a new program is compiled that sends data to the card, the data logger 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 data logger will warn that the card is not being used. However, the CRBasic program runs anyway and data is stored to SRAM. When a card is inserted later, data accumulated in the SRAM table is copied to the card.
A card must be exchanged before it fills, or the oldest data will be overwritten, by incoming new records, and lost. During the card exchange, once the old card is removed, the new card must be inserted before the data table in data logger CPU memory rings, or data will be overwritten and lost.
A microSD card can also facilitate the use of powerup.ini (see File management via powerup.ini for more information).
Formatting microSD cards
The data logger accepts microSD cards formatted as FAT16 or FAT32; however, FAT32 is recommended. Otherwise, some functionality, such as the ability to manage large numbers of files (>254) is lost. There are several ways to format cards such as using: File Control,
MicroSD card precautions
Observe the following precautions when using optional memory cards:
- Before removing a card from the data logger, disable the card by pressing the Eject button and wait for the green LED. You then have 15 seconds to remove the card before normal operations resume.
- Do not remove a memory card while the drive is active, or data corruption and damage to the card may result.
- Prevent data loss by collecting data before sending a program. Sending a program to the data logger often erases all data.
- See System specifications for information on maximum card size.
Act LED indicator
When the data logger is powered and a microSD card installed, the Act (Activity) LED will turn on according to card activity or status:
- Red flash: Card read/write activity
- Solid green: This LED indicates it is OK to remove card. The Eject button must be pressed before removing a card to allow the data logger to store buffered data to the card and then power it off.
- Solid orange: Error
- Dim/flashing orange: Card has been removed and has been out long enough that CPU memory has wrapped and data is being overwritten without being stored to the card.