l USR drive: Optionally allocated. Holds image files. Holds a copy of final-data memory
when TableFile() instruction used. Provides memory for FileRead() and
FileWrite() operations. Managed in File Control. Status reported in Status table fields
USRDriveSize and USRDriveFree.
5.3.1 USRdrive
Battery-backed SRAM can be partitioned to create a FAT USR drive, analogous to partitioning a
second drive on a computer hard disk. Certain types of files are stored to USR to reserve limited
CPU drive memory for data logger programs and calibration files. Partitioning also helps prevent
interference from data table SRAM. The USR drive holds any file type within the constraints of the
size of the drive and the limitations on filenames. Files typically stored include image files from
cameras, certain configuration files, files written for FTP retrieval, HTML files for viewing with web
access, and files created with the TableFile() instruction. Measurement data can also be
stored on USR as discrete files by using the TableFile() instruction. Files on USR can be
collected using data logger support software Retrieve command in File Control, or automatically
using the LoggerNet Setup > File Retrieval tab functions.
USR is not affected by program recompilation or formatting of other drives. It will only be reset if
the USR drive is formatted, a new operating system is loaded, or the size of USR is changed. USR
size is set manually by accessing it in the Settings Editor, or programmatically by loading a
CRBasic program with a USR drive size entered in a SetSetting() instruction. Partition the
USR drive to at least 11264 bytes in 512-byte increments. If the value entered is not a multiple of
512 bytes, the size is rounded up. Maximum size of USR 2990080 bytes.
NOTE:
Placing an optional USR size setting in the CRBasic program overrides manual changes to
USR size. When USR size is changed manually, the CRBasic program restarts and the
programmed size for USR takes immediate effect.
Files in the USRdrive can be managed through data logger support software File Control or
through the FileManage() instruction in CRBasic program.
5.4 Flash memory
The data logger operating system is stored in a separate section of flash memory. To update the
operating system, see Updating the operating system (p. 120).
Serial flash memory holds the CPU drive, web page, and data logger settings. Because flash
memory has a limited number of write/erase cycles, care must be taken to avoid continuously
writing to files on the CPU drive.
5. Data memory 60
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