Data Collection with a USB Thumb Drive

A common application for the USB host drive is data collection with a USB thumb drive. As previously noted, long-term unattended data storage (e.g., resident mode) to a USB thumb drive is not recommended due to reliability concerns regarding non-industrial rated thumb drives. A more common application is using a thumb drive to 'milk' data (e.g., plug and collect data).

For the USB host drive, two data "milking" modes are available: standard and enhanced. With both milking modes, data collection is automatically initiated by connecting a USB flash drive to the datalogger. In standard mode, only the newest data (e.g., data written to datalogger memory since the last time the drive was connected) is collected. In enhance mode, all data stored in the datalogger's memory is collected every time the drive is reconnected. The standard milking mode is enabled by entering 0 for both the NumRecs (Number of Records) and the Interval parameters of the Tablefile instruction. For example,

TableFile("USB:"+Status.SerialNumber+"_FileName",8,-1,0,0,Hr,0,0) 'standard mode

Enhanced mode is enabled by entering 0 for the NumRecs parameter and -1 for the interval parameter. For example,

TableFile("USB:"+Status.SerialNumber+"_FileName",8,-1,0,-1,Hr,0,0) 'enhanced mode

These same data collection modes are available when using an SC115 on the CS I/O port of the datalogger (specified as CS9: in GRANITE 9 and 10 dataloggers). However, transfer rates to an SC115 are approximately 10 times slower than to a USB thumb drive. See the SC115 manual for details.

Campbell Scientific data loggers only support FAT32-formatted USB drives. By default, industrial USB drives that are 8 GB and larger are formatted as exFAT by the manufacturer. Therefore, industrial USB drives that are 8 GB and larger must be reformatted as FAT32. In addition, Windows does not support creating FAT32 partitions for industrial USB drives that are larger than 8 GB. Therefore, when using Windows to format USB drives that are larger than 8 GB, two steps are required to achieve the FAT32 format:

  1.  Format the USB drive as NTFS, which is recognized by the datalogger but is still not compatible for data storage.

  2.  Use File Control to format the USB drive as FAT32.