Datalogger Field

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This documentation discuss issues that are likely to effect the use of the datalogger outside of the laboratory.

Battery Replacement

The datalogger is powered from a pair of alkaline batteries that will develop a load voltage of >3.0V when new. With use series resistance of the battery pack increases causing the supply voltage to drop. To guarantee adequate supply current and proper operation, the batteries should be replaced when voltage drops below 2.4V when loaded by the datalogger in idle mode.

When the batteries are removed the datalogger may continue to operate for 10 seconds. Therefore, when the batteries are replaced, don't be in a hurry insert new ones.

SD Card

To avoid any data loss (the datalogger won't corrupt the SD card) and proper recognition of the SD card, observe the following guidelines.

  • Wait at least 1.5 seconds before inserting the card after removal
  • Wait at least 7 seconds from the last timing pulse before removing the card.
  • Ideally wait for the LED pattern to acknowledge the SD card state before removing the card.

LEDs Blink Patterns

After Reset

  • GREEN is immediately set
  • Within a millisecond, all 3 LEDs are set (thus the you'll never realize that only GREEN was lit)

NO SD Card

When the SD Card is absent the single RED LED will blink the pattern LONG SHORT

SD Card Verification

After insertion, the SD Card is verified. During this phase the dual RED LED will remain lit, and the green LED will flicker as the SD card is tested

SD Card Failure

If the SD Card verification fails the card will need to be removed and possibly replaced with a new one. The single LED will blink with the pattern LONG SHORT SHORT SHORT

SD Card Success

To notify the user of a successful SD Card insertion, the dual LED with alternately flash the RED-GREEN 8 times.

Normal Operation Idle and Active Mode

During normal operation, the GREEN LED will blink (dimly in idle mode) once per second. However during timing data capture and SD card access the GREEN LED will flash more brightly. The GREEN intensity is proportional to the amount activity of the CPU in this mode.

JTAG Operation

  • When in the JTAG programming mode, the single RED LED will flash with a rapid steady pattern
  • If the clock update fails, the single RED LED will flash with 4 stead pulses followed by a pause of 4 flash times.
  • When the JTAG operation is successful the dual LED with alternately flash the RED-GREEN 6 times.

LED Summary

  • green steady : immediately after reset
  • all steady : for 1 second after reset
  • single red LONG SHORT : SD card missing
  • single red LONG SHORT SHORT SHORT : remove SD Card
  • single red fast flash : JTAG operation
  • single red SHORT SHORT SHORT SHORT PAUSE : JTAG / clock error
  • dual RED with green flicker : SD card analysis
  • RED-GREEN alternate (4 times) : SD card insertion success
  • RED-GREEN alternate (3 times) : JTAG success