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X16-1D

USB Accelerometer

Data Logger

User Manual

Document Revision: 

Rev B

Firmware Version: 

1110

Date: 

March 22, 2016

Summary of Contents for X16-1D

Page 1: ...X16 1D USB Accelerometer Data Logger User Manual Document Revision Rev B Firmware Version 1110 Date March 22 2016 ...

Page 2: ...Options 11 2 6 1 deadband 12 2 6 2 deadbandtimeout 13 2 6 3 dwell 13 2 6 4 microres 14 2 6 5 rebootondisconnect 14 2 6 6 samplesperfile 14 2 6 7 samplerate 14 2 6 8 starttime and stoptime 14 2 6 9 stoponvusb 15 2 6 10 statusindicators 15 2 7 Example Configuration Files 15 2 7 1 Example A 15 2 7 2 Example B 15 2 7 3 Example C 16 3 Data Interpretation 16 3 1 Data Files 16 3 2 Data Format 17 3 3 Data...

Page 3: ...ED Status Indicators 11 Figure 14 Graphical Illustration of the Deadband Feature 13 Figure 15 Graphical Illustration of the Dwell Feature 13 Figure 16 Configuration File Example A 15 Figure 17 Configuration File Example B 15 Figure 18 Configuration File Example C 16 Figure 19 Example Data File 17 Figure 20 800Hz sample configuration 20 Figure 21 Enclosure Dimensions 20 Figure 22 Spring mass Accele...

Page 4: ...data 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 r...

Page 5: ...kaline battery or LR6 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 transfer compatible with Windows or Linux v...

Page 6: ...r a USB extender cable a screwdriver and an AA alkaline battery 1 6 2 5 Unit Kit A kit includes 5 X16 1D loggers a USB extender cable and a screwdriver Batteries are not included with kits Gulf Coast Data Concepts Page 3 X16 1D Rev B Figure 2 X16 1D and Accessories Figure 3 5 Unit kit of Loggers ...

Page 7: ...ve terminal M 6 32 3 4 screw F Negative terminal N 6 nut G On Off button O ADXL345 sensor H MicroSD card under circuit board Gulf Coast Data Concepts Page 4 X16 1D Rev B Figure 4 X16 1D Data Logger Components A I B C D H E K G F J M N O L Figure 5 Exploded View of the X16 1D 0 75 Length 6 32 M achine Screw PCBEnclosure Top PCBEnclosure Cap Printed Circuit Board PCBEnclosure Bottom 6 32 HexNut ...

Page 8: ...by unscrewing the 6 machine screw and opening the parts like a clam shell Place an AA type battery into the battery holder with the positive battery terminal facing away from the USB connector Reassemble the enclosure Step 2 Plug the X16 1D into a computer and allow the computer operating system to register the device as a Mass Storage Device Notice that the logger will mount with a drive label us...

Page 9: ...e Velcro or a spot of cyanoacrylate glue are sufficient methods of attachment Step 6 Press the on off button located at the rear of the enclosure to initiate data recording see Figure 9 Logging will start about 3 5 seconds after pressing the button The red LED will blink as the configuration file is accessed If the time txt file is present the RTC is initialized with the time written in the file T...

Page 10: ...ed to a new file Step 8 Plug the logger into a PC and allow the logger to mount as a USB drive The data file will appear in the GCDC directory Step 9 The data recorded to the files must be converted to determine acceleration in g units Divide the Ax Ay Az columns by 2048 to determine g units See section 3 3 for a complete discussion of data conversion Gulf Coast Data Concepts Page 7 X16 1D Rev B F...

Page 11: ...ne battery ANSI type 15A or IEC type LR6 or lithium battery ANSI type 15L or IEC FR6 to operate the X16 1D The battery is not used when the device is connected to a computer USB port The X16 1D will log constantly for approximately 48 hours at 50 Hz and approximately 28 hours at 100 Hz when using a standard alkaline AA battery Figure 11 illustrates the expected continuous logging time versus sampl...

Page 12: ...tion of the device independent of the internal battery Common USB power adapters or USB battery packs for consumer electronics can provide the required 5v supply The logger does not implement power saving features when connected to an external power supply so power consumption will be higher than when using the AA battery The logger is always on maintaining the real time clock and will eventually ...

Page 13: ... 10 X16 1D Rev B Initializing the RTC ensures that the start time and individual time stamps can be correlated to an absolute time the year month day hour minute second and fractional second An uninitialized RTC or reset of the RTC will lead to indeterminate start time recorded in the data file header After unplugging the logger from the USB port the logger will load the config txt file and time t...

Page 14: ...e section 3 2 4 10 2 6 System Configuration Options The X16 1D is configured using a set of tags and settings stored in a text file named config txt which is located in the root directory of the microSD card The system reads the configuration file at boot time Table 1 lists the configuration file tags A tag is followed by an equal sign and an applicable tag setting A line finishes with a newline c...

Page 15: ...d stoptime See section 2 6 8 Defines when to start and stop recording stoponvusb Off Stops data logging if 5v USB power is present see section 2 6 9 statusindicators Normal High Off Normal LED status indicators can be activated with normal brightness Normal activated with high brightness High or completely deactivated Off 2 6 1 deadband deadband defines the minimum difference between recorded sens...

Page 16: ... an event trigger configuraion The dwell tag defines the number of consecutive samples recorded at the set sample rate after a deadband threshold event The deadband threshold event occurs when a sensor reading exceeds the last recorded value by the deadband setting A valid dwell setting is an integer between 0 and 65535 See section 2 7 2 for an example implementation of the deadband dwell features...

Page 17: ...tware application for data limitations 2 6 7 samplerate The samplerate tag defines the data rate in Hertz or samples per second Valid sample rate settings are 12 25 50 100 200 and 400 Hz See section 4 1 for special features regarding the sample rates 2 6 8 starttime and stoptime The X16 1D starts and stops data recording based on the times defined using the starttime and stoptime tags The times mu...

Page 18: ...d with the on off button notice rebootondisconnect is not active 2 7 2 Example B The deadband and dwell settings configure the device to record at least 5 seconds of data when a change greater than 0 1g is detected The deadbandtimeout setting forces a sample write every hour Gulf Coast Data Concepts Page 15 X16 1D Rev B Figure 16 Configuration File Example A Example X16 1D config file set sample r...

Page 19: ...1D is removed from a computer USB port with the rebootondisconnect feature enabled Data files are placed in a folder named GCDC and are named data XXX csv where XXX is a sequential number starting with 001 The system will create up to 999 files At the beginning of each file a header is written describing the system configuration and the current time when the file was created Figure 19 represents a...

Page 20: ...ast reading by the deadband value DeadbandTimeout The period in seconds when a sample is recorded regardless of the deadband setting Headers The names of each column of data in the file SampleRate Rate at which data is recorded to the microSD card Start_Time The current time when the data file was created Temperature Not supported on X16 1D reports 999 Title The name of the USB Accelerometer X16 1...

Page 21: ...7148 0 887695 0 042 801 663 1808 01 04 2016 10 25 14 042 0 391113 0 323730 0 882813 0 052 769 657 1786 01 04 2016 10 25 14 052 0 375488 0 320801 0 872070 0 062 790 683 1795 01 04 2016 10 25 14 062 0 385742 0 333496 0 876465 0 072 813 719 1853 01 04 2016 10 25 14 072 0 396973 0 351074 0 904785 0 081 824 670 1784 01 04 2016 10 25 14 081 0 402344 0 327148 0 871094 4 System Details 4 1 Sensor The X16 ...

Page 22: ...ximum capability of the ADXL345 The eight samples are averaged and processed through the FIR filter to improve the response characteristics The oversampling and FIR algorithm increases the sensor s native 13 bit resolution to the 16 bit data recorded in the data file The X16 1D will support sample rates of 800 1600 and 3200 Hz but the X16 1D deactivates the oversampling and FIR filter and records ...

Page 23: ...4 3 Dimensions The X16 1D electronics are enclosed 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 X16 1D weighs 2oz 55g with an alkaline battery Gulf Coast Data Concepts Page 20 X16 1D Rev B Figure 20 800Hz sample confi...

Page 24: ...for a short period of time Install a new battery The microSD card is full and data files must be deleted The logger seems to ignore the config txt file and use default settings Check that the config txt file is properly formatted and not corrupted Each setting should occur on a separate line Some IT organizations implement an automatic encryption of all removable media devices This will encrypt th...

Page 25: ... Remove the extender cable and plug the logger into another USB port The start time in the data file header is incorrect Initialize the RTC The Z axis data is missing in the file No it s present but the column headers are shifted due to the presence of the headers tag The logger is stationary but it registers 1g This is normal and indicates Earth s gravity is fully operational and stable But the l...

Page 26: ...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 and Error Reference source not found shows the internal layout of an actual MEMS accelerometer sensor...

Page 27: ...tect 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 discer...

Page 28: ...ing R because 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 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 libraries R is wide...

Page 29: ...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 30: ...ine 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 an...

Page 31: ...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 1D data logger These examples educate the user on basic operation of the data logger interp...

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