Warning
The flash card must be formatted before use. Furthermore, it is important to format it in FAT or FAT16 (not FAT32). Supported card size is limited to 1Gbyte (larger formats are not supported by FAT16). You can format your flash cards on a PC, if you want; however, make sure you format it in FAT16. The HHTFO includes a format command, where FAT16 is always used.
The HHTFO is designed so it can only write to SD flash cards. To read back temperature data, remove the card from the HHTFO and bring it to a suitable SD card reader; from there, you can copy files to your PC hard disk, use Excel to draw trend lines, and so forth. You should use your PC to erase any specific file(s) (the HHTFO does not have any function to erase files from the SD card).
4.5.1 File naming convention
File names are structured as follows: YYMMDDXX.OEI, where:
•YY represents the current year (e.g., 06)
•MM represents the current month
•DD represents the current date
•XX is a sequence number that starts at “01”, and can go up to “99”
•.OEI is a fixed file extension.
Furthermore, file sizes are limited to 65500 lines, to ease their import to spreadsheet such as Microsoft Excel. When the 65500 limit is reached, a new file is open using the next available file sequence number. Typical file content may look like this:
A time stamp accompanies each temperature entry (24 hour time format). File format is tab delimited.
The logging menu includes 3
As the sequence number is limited to 99, you are limited to a total of 99 logged files per day. Also, if you are logging temperatures when the clock reaches midnight on any given day, the next file that will have its name constructed based on the new date, and the sequence number will be reset to “01”.
4.5.2 The Format sub-menu
Warning
Exercise extreme care when using this function. It will erase ALL files and data you may have saved on the SD card!
Once you select “Format: Yes”, you need to confirm the format operation by holding down BOTH the Left and the Right arrows simultaneously for at least one second; if this confirmation is not done within about 10 seconds, the format operation is aborted. “Format successful” is displayed upon a successful operation.
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