Gulf Coast Data Concepts X16-5, User Manual

Page 1: ...X16 5 USB Accelerometer Data Logger User Manual ...

Page 2: ...9 2 5 Status Indicators 10 2 6 System Configuration Options 11 2 6 1 absoluteTime 12 2 6 2 deadBand 12 2 6 3 deadBandTimeOut 12 2 6 4 dirName 12 2 6 5 disableCharger 13 2 6 6 dwell 13 2 6 7 fileName 13 2 6 8 minBattVoltage 13 2 6 9 rebootOnDisconnect 13 2 6 10 samplesPerFile 14 2 6 11 sampleRate 14 2 6 12 stopOnVusb 14 2 6 13 statusIndicators 14 2 6 14 wakeUpTime 14 2 7 Example Configuration Files...

Page 3: ...xpected Battery Life 8 Figure 11 Example Time Entry in time txt File 10 Figure 12 LED Status Indicators 10 Figure 13 Graphical Illustration of the Deadband Feature 12 Figure 14 Graphical Illustration of the Dwell Feature 13 Figure 15 Configuration File Example A 15 Figure 16 Configuration File Example B 15 Figure 17 Configuration File Example C 16 Figure 18 Example Data File 17 Figure 19 Time Stam...

Page 4: ...ta logger This user manual continues into further details of configurations and capabilities starting in section 2 Each section also presents relevant tips and warnings to help the user This icon indicates a helpful tip that may enhance the performance of the logger or aide in the application of the logger This icon indicates a warning restriction or limitation that the user should be aware of reg...

Page 5: ...er rechargeable battery which will recharge using USB power 1 5 Feature List 3 axis 16g accelerometer 16 bit resolution User selectable sample rate of 12 25 50 100 200 400 Hertz Finite Impulse Response filter Accurate time stamped data using Real Time Clock RTC Convenient on off button Data recorded to a removable microSD card 8GB included Easily readable comma separated text data files Data trans...

Page 6: ...6 1 Single Unit Purchase The X16 5 is packaged with the logger a USB extender cable and a screwdriver 1 6 2 5 Unit Kit A kit includes 5 X16 5 loggers a USB extender cable and a screwdriver Gulf Coast Data Concepts Page 3 X16 5 Rev New ...

Page 7: ... D Red LED charge indicator K Enclosure hinge E 500mAh Battery Pack L 6 32 3 4 screw F On Off button M 6 nut G MicroSD card under wrap N ADXL345 sensor Gulf Coast Data Concepts Page 4 X16 5 Rev New Figure 5 Exploded View of the X16 5 0 75 Length 6 32 M achine Screw PCBEnclosure Top PCBEnclosure Cap PCBEnclosure Bottom O n O ff Button 6 32 H exNut ...

Page 8: ...ount with a drive label using the last digits of the serial number A red LED located on the bottom side will indicate the battery is charging The LED will turn off when the battery is fully charged which takes about 2 hours Step 2 Configure the X16 5 by editing the appropriate tags in the config txt file using a simple text editor In Windows do not use Notepad as the editor does not terminate new ...

Page 9: ... the system is operating The red LED will blink periodically as data is written to the microSD card Step 6 To stop recording press and hold the button for about 3 seconds The red and blue LEDs will begin to blink rapidly for 2 seconds and then turn off Release the button and the X16 5 turns off Pressing the button again restarts the logger and data is recorded to a new file Step 7 Plug the logger ...

Page 10: ... logger needs only the config txt file to operate The X16 5 will use default configuration settings if the config txt is not present The config txt and time txt files must occur in the root directory see section 2 6 and section 2 4 The X16 5 will create a data folder to place the data files Gulf Coast Data Concepts Page 7 X16 5 Rev New Interrupting the power to the logger can result in corruption ...

Page 11: ...be reinitialized if the battery is removed or completely depleted see Section 2 4 2 3 1 Expected Battery Life The battery provides approximately 7 hours of operation sampling at 400 Hz with the deadband set to zero maximum data recording capability Operating time increases with lower sample rates Figure 10 illustrates the expected continuous logging time versus sample rate Figure 10 Expected Batte...

Page 12: ... file method of setting the RTC does not require special communication drivers so it can be implemented using a simple text editor Direct initialization of the RTC is possible but requires specific device drivers and software from Gulf Coast Data Concepts Initializing the RTC with a time txt file is accomplished as follows Step 1 Use Wordpad or an equivalent text editor to create a simple text fil...

Page 13: ...luminates when charging is in process see Figure 12 The charge indicator LED will turn off when the battery is fully charged A fully discharged battery will charge in about 2 hours A blinking charge indicator LED means there is a problem with the lithium polymer battery pack Gulf Coast Data Concepts Page 10 X16 5 Rev New Initializing the RTC ensures that the start time and individual time stamps c...

Page 14: ...d setting dirName Character text GCDC Defines directory name to store data files disableCharger Off Deactivates the charger circuit to the battery dwell An integer between 0 and 65535 1 The number of samples recorded after a deadband threshold triggered event fileName Character text DATA File name prefix for the data files minBattVoltage An integer greater than 0 3200 set the minimum operating bat...

Page 15: ...th the dwell feature Figure 13 illustrates the deadBand feature filtering out small changes in acceleration from the recorded data Only when the deadBand limit is exceeded will a new data sample be pushed to the file Note that this feature will result in samples with inconsistent time periods Therefore the data sets should be re sampled to establish uniform time periods 2 6 3 deadBandTimeOut deadB...

Page 16: ...een 0 and 65535 See section 2 7 2 for an example implementation of the deadBand dwell features 2 6 7 fileName fileName sets the prefix name of the data files By default fileName is set to DATA 2 6 8 minBattVoltage The logger will initiate a low battery shutdown when the minBattVoltage is detected By default the minBattVoltage is set to 3200 millivolts In the case of non rechargeable type battery c...

Page 17: ... Parameters are in order of minutes hours and days and are separated by spaces Multiple parameters are separated by commas For example wakeUpTime 5 20 4 15 turns the logger on at 5 minutes and 20 minutes past the hour of 4am and 3pm wakeUpTime will turn the logger on with each minute There are three additional parameters needed to complete the wakeUpTime option and each must be on a separate line ...

Page 18: ...r Gulf Coast Data Concepts Page 15 X16 5 Rev New Figure 15 Configuration File Example A Example X16 5 config file set sample rate available rates 12 25 50 100 200 400 samplerate 100 record constantly deadband 0 deadbandtimeout 0 set file size to 15 minutes of data samplesperfile 90000 set status indicator brightness statusindicators high A wakeUpTime event is triggered upon the first time the logg...

Page 19: ...t time when the file was created 3 2 Data Format Data is written to files in comma separated text format starting with the file header information and followed by event data entries Each data line contains a time entry and the raw accelerometer sensor readings from the X Y and Z axes The time entry is seconds elapsed from the start time recorded in the header default mode or relative to Jan 1 1970...

Page 20: ...start date The spreadsheet will automatically format the new text into a date Next divide the time stamp entry by 86400 This converts the time stamp into a value compatible with the spreadsheet date functions Finally add the new time stamp to the new start date and a complete data time is generated Format the column as a time category and include the trailing 000 to present the millisecond precisi...

Page 21: ...on factor is 65536 32 2048 counts g Table 2 lists the converted data using the example raw data in Figure 18 Table 2 Example Data Conversion Raw Data Low Gain Converted Data Time Ax Ay Az Time Ax g Ay g Az g 0 163 10 24 2054 12 15 2020 10 15 24 553 0 004883 0 011719 1 002930 0 173 21 28 2063 12 15 2020 10 15 24 726 0 010254 0 013672 1 007324 0 183 17 12 2090 12 15 2020 10 15 24 909 0 008301 0 0058...

Page 22: ...The ADXL345 accelerometer sensor pushes data to the logger at selected rates based on a clock internal to the sensor The sensor s clock precision and drift are undefined For example a selected sample rate of 50 Hz may actually push data at 52 Hz The X16 5 incorporates a precise real time clock to independently time stamp the data as it leaves the sensor and to ensure that accurate timing is record...

Page 23: ...800 Hz The 13 bit data from the sensor is right padded LSB into a 16 bit value to maintain consistency with the oversampled data Therefore the conversion factor is still 2048 counts g 4 2 Operating and Storage Conditions The X16 5 is protected from general handling conditions by the plastic enclosure but is not protected from adverse environmental conditions such as rain sweat splashes and water s...

Page 24: ...closed in a three part semi transparent blue plastic enclosure The top and bottom enclosure components and the printed circuit board are secured together with a 0 75 long 6 32 screw and nut A slip on cap protects the USB connector The overall dimensions are 1 01 wide 1 04 tall and 4 30 long 25 6x26 4x109 2 mm The X16 5 weighs 1 3oz 48g Gulf Coast Data Concepts Page 21 X16 5 Rev New Figure 21 Enclo...

Page 25: ...s full and data files must be deleted I plug the logger into a USB port but the PC does not indicate an external drive present The microSD card is not present in the logger or is not inserted properly Check that the card is fully inserted into the logger The microSD card is corrupted or damaged Reformat the card or replace the card The on off button could be jammed in the plastic enclosure and the...

Page 26: ... time is correctly formatted and the file name is time txt Windows may hide the file extension so naming the file as time txt may actually be named time txt txt Check the Windows file explorer options the view of regarding file extensions The logger is stationary but it registers 1g This is normal and indicates Earth s gravity is operating correctly But the logger actually registers something othe...

Page 27: ... spring constant and spring displacement the force acting upon the mass is calculated Acceleration is the force divided by the mass Micro electro machined sensor MEMS technology takes the spring mass concept and miniaturizes it onto a semiconductor chip Figure 23 illustrates the general concept of a MEMS accelerometer system next to an actual MEMS accelerometer sensor The mass and spring system is...

Page 28: ...ect translation motion within the axis of the proof mass Rotational motion causes centripetal acceleration that is interpreted as translational motion by the accelerometer For example spinning about the z axis will cause acceleration in the x y axes even though there is no translational motion in the x y plane A gyroscope sensor which measures rotational velocity about an axis is needed to discern...

Page 29: ...se it is more powerful than a spreadsheet and it is easy to learn R is a high level programming language used most commonly for statistical analysis of data R is an open source project based on the S language which was developed by the Bell Laboratories in the 1970s R provides a simple workspace environment that can manipulate large data sets using simple math commands and complex function librari...

Page 30: ...le command line interface window and a separate graphics window for displaying plots RStudio is free software package that provides a more versatile interface to the R interpreter RStudio is available at www rstudio com 6 2 2 Introduction to R Commands R recognizes basic math operators such as and Assignments are made using For example 2 2 1 4 a 2 2 assign a the result of 2 2 a 1 4 In the above ex...

Page 31: ...ne plot of x axis values lines data 1 dataY_g type l col blue add another line to plot The converted data can be combined into a new matrix and then exported to a new csv data file output array c data 1 dataX_g dataY_g dataZ_g dim c length data 1 4 write table output c output_data csv sep An analysis can be automated by saving the commands into an external text file Use source to call the file and...

Page 32: ...e with R it s very likely someone else faced the same challenge and posted the question to R forums Search the internet and you will find a solution to get you back on track 6 2 4 Example Scripts in R Several example applications using R scripts are available at the GCDC website or are included with the X16 5 data logger These examples educate the user on basic operation of the data logger interpr...