Logging to SD card

The Log4 device allows the logging of measurements onto a micro SD card. New .csv files are created at the beginning of every session. Before logging data on to the SD card, please make sure the SD Card is in FAT32 format.

Logging data on to SD card:

  • Make sure Log4 device is initially switched OFF.
  • Insert Micro SD card into MICRO SD slot (Ensure the SD card is facing label side down and insert it into the SD card slot until it clicks into place).
  • Press START/STOP button to turn on Log4 device.
  • A “S” symbol should occur at the top of the information bar next to time (Fig. 35).
Log4.USB Main screen with "S" symbol

Fig. 35 Main screen with “S” symbol

“S” indicates the SD card is recognised but is not currently logging in any data. (If there isn’t a “S” symbol or if instead of “S” , there is a “U”, try reformatting the SD card again or simply try to turn the device OFF and ON again)

  • To commence logging data, the shortest method is to just press the START/STOP button once. The “S” symbol will change into “L”. This indicates the Log4 Device is currently logging data onto the SD Card.
  • To stop logging data, press START/STOP button once again. The “L” will change back to “S”.
  • The SD card can now be taken out or START/STOP button can be clicked again to log more information.

Viewing Measurements on CSV files

  • Eject Micro SD from Log4 Device.
  • Put Micro SD into Micro SD Card adapter and then insert the SD card into SD slot of PC.
  • A CSV file labelled logYYYY-MM-DD_hh_mm_ss.csv should be seen in the SD card drive.
  • Open up the latest CSV file logYYYY-MM-DD_hh_mm_ss.csv

The measurement data is split into 3 columns starting from left to right (Fig. 36).

  • Sample number.
  • Current (in uA).
  • Voltage (in mV).
A sample CSV file with measurement dataLogging to Serial (Arduino)

Fig. 36 A sample CSV file with measurement dataLogging to Serial (Arduino)