LISST-ABS User`s Manual - Sequoia Scientific, Inc.
Contents
1. DisplayStatus Display Status Syntax DS or ds or status Description Display the Current Status of the instrument including instrument serial number and firmware version Example Command DS Response Serial number 6014 SDI 12 address 0 Version Jul 8 2015 15 01 34 LISST ABS gt GetSample Take and Transmit Sample and hold Syntax GS or gs or getsample Description Instrument makes a measurement stores it in memory and outputs the ACB value to the RS 232 output Example Command GS Response lt delay of 1 second gt 1234 LISST ABS gt HoldSample Take Sample and hold it Syntax HS or hs or holdsample Description Instrument makes a measurement and stores it in memory The results are NOT sent to the RS 232 output Only a LISST ABS gt prompt is returned Example Command HS Response LISST ABS gt SendLast Transmit last sample Syntax SL or sl or sendlast Description Transmits the last sample collected by the issuing of a GetSample or HoldSample command Example Command SendLast Response lt delay of 1 second gt 1234 LISST ABS gt Return to Automatic Mode Syntax GO or go or return or exit Description Returns the LISST ABS to automatic mode where results are output to the RS232 every 1 second Example Command Exit Response delay of 1 second 1234 delay of 1 second 1234 Help Display Help Syn2. 24 APPENDIX B CONVERTING ACB DATA TO SEDIMENT 26 APPENDIX C HOW THE LISST ABS 27 WARRANT Y ics caiccusc ct ivan saie aun stia aesa aac ca qa acuti CL vada ada d cd Era YR RE CAR Aikainen EE 30 Section 1 Quick Start Intro Step 1 Unpack box Step 2 Install Software Step 3 Plug in USB cable and Start Program Thank you for purchasing Sequoia s LISST ABS acoustic sediment sensor This Quick Start guide is intended to get you up running as quickly as possible Detailed instructions can be found in other sections of the manual The LISST ABS uses acoustic backscatter to measure the concentration of particles suspended in water It outputs the Attenuation Corrected Backscatter or ACB The ACB can be converted to Concentration using a simple formula For more details see Appendix B and Appendix C The LISST ABS is shipped ready for use It takes just 3 easy steps to start seeing some real measurements Inside the box should be the following items LISST ABS with protective red cap and locking cap on the connector a 5 to 50 meter long cable with underwater connector on one end and an 8 pin plastic Molex connector on the other end USB cable with mating Molex connector and three short pigtails with mating Molex connectors The three cables can be used for connecting
3. 2875 2780 Sample Number 6 Sample Interval 1 Sec 30 Measurement Average Stop Logging Current File C Users Sequoia Desktop ABS_AzDust txt LISST ABS v1 0 The log file header contains calibration information The header is followed by four columns of data date time ACB and concentration mg L File Edit Format View Help 500 Nref 1153 Calibration Date 07 28 2015 08 56 46 Calibration Comments 5 10 Micron Arizona Dust 09 04 2872 2741 09 04 2878 2818 09 04 2874 2766 09 04 2863 2630 09 04 2865 2654 07 28 2015 09 04 2896 3061 Should there be power interruption or momentary disconnection the LISST ABS software will automatically reconnect when the power or connection is reestablished If the disconnection occurs while logging data the logging will pause and resume automatically when the instrument is reconnected Should one of the two error codes be produced by the ABS the error code will be displayed and a brief description of the problem will be shown An ACB value of 999 means low power supply voltage instrument could not operate A value of 888 implies obstruction within sample volume or the second sample volume is at a boundary see Appendix C In either case this error is triggered when backscatter from the second range cell is stronger than the first 21 Attenuation Corrected Concentration Backscatter mg L Serial Number 6004 L i 2 1153 ow input vo
4. LISST ABS SDI 12 Command Summary Command Name Command Code Notes Address Query Request address of single sensor on bus Acknowledge Active a Request response from sensor at address a Change Address Change address of sensor at address to b Send Identification al Send ID string including SI address SDI version Manufacturers ID sensor model sensor Firmware version and device serial number Start Measurement aM Start a measurement returns number of seconds till sample is ready to be read Sends service request when measurement is complete Start Concurrent Same as Start Measurement command Measurement except does not send service request Send Data aDb Requests output b 0 9 from Sensor a Continuous Measurements aR Not supported Read Start Verification Not Supported See the next page for details of SDI 12 commands LISST ABS SDI 12 Command Details Basic Command Set Address Query Syntax Description Request address of single sensor on bus Note sensor must be the only sensor on the bus or multiple instruments will respond simultaneously Example Command Response O responds with address of sensor in this case O a Acknowledge Active Syntax a Description Request response from sensor at address a Example Command 0 request sensor at address 0
5. read Does not send service request when measurement is complete Example Command request sensor at address to make as measurement Response 30011 3 is the address 001 is of seconds 1 is the of values after 1 second measurement is ready but no response is send aDb Send Data Syntax aDb Description Requests output b 0 9 from Sensor a Examples Command 3DO request sensor at address 3 to send data block 0 Response 34123456 responds with Attenuated Correct Backscatter ACB aR Continuous Measurements Syntax aR Description Not supported The LISST ABS is not a continuous measurement device No data will be returned The response to this command is below Example Command 3R request continuous measurement Response 3 responds with address of sensor Start Verification Syntax Description Example Not supported but the sensor will respond to the command with the response shown below Command OA3 request sensor at address 0 to change to address 3 Response 30000 responds with current address of sensor LISST ABS SDI 12 Best practices In order to obtain the most accurate results it is recommended that the LISST ABS be powered up and allowed to sample in the automatic mode green LED double blinking for 30 seconds or more before issuing a Start Measurement command This 3
6. 70 g L The LISST ABS measures the Attenuation Corrected Backscatter ACB This is the raw digital output of the instrument The instrument response is logarithmic similar to ADCP To convert the ACB to sediment concentration two constants are employed a fixed constant Ko and a second constant N e which depends on the specific type of sediment When a user recalibrates an instrument it is this constant that is updated For more detailed understanding of the technology please see Appendix C The LISST ABS can output the ACB using three different methods SDI 12 RS232 and analog output All three of these outputs are available on the underwater connector on the end of the LISST ABS The output used is determined by how the instrument is connected to the datalogger The LISST ABS can be powered in two ways For testing purposes a special USB cable is available When using this cable power to the instrument is provided by the USB port When connecting to a datalogger you will need to supply a voltage between 10 18VDC The current drain at 12V is 100 ma when actively collecting data If the supply voltage is too low the LISST ABS will output an ACB value of 999 When the LISST ABS is powered up the green LED on the endcap will start to blink at about once per second This indicated that the instrument is powered up and operating normally When the LISST ABS is actively sampling it will double blink two blinks in quick successi
7. Sequoia for connecting to your RS232 compatible datalogger To make the connections easier we have provided different cable terminations designed specifically for different connection requirements For example we provide a termination with only the four individual wires that are labeled and can be easily connected to the datalogger The mating connector makes it easy to remove the long cable without disconnecting the wires from the datalogger You can also easily switch between the datalogger and the USB cable if needed The wires are labeled and color coded Connect the Black wire to Ground Connect the Red wire to 12V Connect the Yellow ABS Transmit wire to the datalogger Receive input and the Blue ABS Receive wire to the Datalogger transmit output The LISST ABS uses a baud rate of 9600 with 8 data bits one stop bit no parity and no flow control By default the LISST ABS will automatically start outputting the computed ACB values out the RS232 connection upon power up The values are output at once per second The values are one integer per line The line is terminated with a linefeed character We call this the Automatic Mode output 9 The simplest method of collecting RS232 data is to capture and store the values being returned from the LISST ABS as it is output As described below in the recommended sampling procedure the instrument should be allow to output for 30 seconds after power up before measurements are recorded T
8. a quick look at the screen Calibration Concentration will remain blank until a value is entered for see Appendix B for an explanation of calibration constants If you are only interested in viewing and logging ACB you can skip this section If you already have a value for Ner it can be simply typed into the text box at the center of the screen Concentration will then be calculated using the entered value and then displayed on the screen Note that all LISST ABS instruments use a factory default value of Nret as 1000 This corresponds to 5 to 10 micron Arizona Test used for the factory calibration You may use this value to get an idea of the concentration If you don t have a value for you will have to calibrate the instrument This can be easily achieved by pressing the Recalibrate Nier button A new window will appear It will list the simple steps you need to follow to calibrate the instrument left A check box at the bottom of the window allows you to save 18 Calibration Procedure J 1 Prepare a mixture of water and sediment at a concentration of approximately 100 mg L 2 Enter the mixture s true concentration below mg L 3 Submerge the head of the ABS into the mixture ensuring it is at least 15 cm from the bottom of the tank 4 Ensure the sample is continually mixed using a stir bar or other apparatus 5 Add comments about this calibration optional 6 Press the continue button
9. every 15 minutes are desired we recommend the following procedure 1 Power up the LISST ABS 45 seconds before the beginning of the desired sample time and allow it to sample 2 Option 1 Start recording the values being output by the LISST ABS to record 60 measurements 1 second apart Option 2 Issue GetSample commands to record 60 measurements 1 second apart 3 Power down the LISST ABS and wait till the next sample time For suggestions on mounting cleaning and maintenance please see Section 2 6 13 2 4 Analog Output Operations LISST ABS and Analog Output Best Practices The LISST ABS has a third output option The digital ACB value is converted to a voltage and output on the underwater connector This voltage can be recorded and converted back to ACB values It is highly recommended to use either SDI 12 or RS232 to obtain the most accurate measurements of ACB However for some applications it may be desirable to use the analog output Using the Analog Output requires four wires Power Power Ground Signal and Signal Ground Appendix A includes detailed descriptions of the use of the individual pins of the 8 pin connector on the LISST ABS However in most cases you will be using a cable provided by Sequoia for connecting to your datalogger To make the connections easier we have provided different cable terminations designed specifically for different connection requirements For example we provide a termination with onl
10. in accordance with SEQUOIA s applicable specifications and c any Products or components or parts thereof that are manufactured by SEQUOIA do not infringe any U S patent or copyright 2 Correction of Non Compliance If during the twenty four months after installation or thirty months after delivery whichever comes first the Warranty Period any Product does not comply with the warranties set forth in 1 a and 1 b above SEQUOIA will at its option either a repair the Product b replace the Product or c refund the purchase price paid by Customer to SEQUOIA for the Product provided that Customer gives SEQUOIA written notice of the noncompliance within the Warranty Period and ships the Product to SEQUOIA within one month after the end of the Warranty Period As to any Product repaired or replaced by SEQUOIA the Warranty Period will end upon the later of the end of the original Warranty Period or 90 days after SEQUOIA s delivery of the repaired or replacement Product to Customer Any Product component part or other item replaced by SEQUOIA becomes the property of SEQUOIA SEQUOIA may use refurbished components in the repair of Products supplied hereunder SEQUOIA s warranties shall be void and not apply if the Product has been subjected to misuse or alteration or repaired by a party not approved by SEQUOIA or the serial number on a product if applicable has been altered or defaced SEQUOIA shall not be liable for normal wear and te
11. to collect 100 measurements that will be used to compute a new Nref value It will automatically replace the current Nref value displayed in the software Save ACB calibration values to a text file Continue Cancel a calibration text file that contains the 100 ACB measurements that were used to calculate the Nre You may wish to save this file for your records but it is not required for the calibration to proceed After following the calibration steps the software will begin collecting 100 measurements If you elected to save a calibration file you will be prompted for a location to save the file Attenuation Corrected Concentration Backscatter g L Serial Number 6004 2 1 rd E Calibration Calibration Sample Number 94 Sample Interval 1 Sec 30 Measurement Average Current File LISST ABS v1 0 The sample number will count down from 100 Once completed a new will be calculated and entered into the text box This value will be saved in the software between sessions next time you open software Nre will be filled automatically Concentration will now be displayed alongside ACB Attenuation Corrected Concentration Backscatter mg L Serial Number 6004 2 52065 Recatibrate Nref Create Log File Sample Interval 1 Sec V 30 Measurement Average Start Logging Current File LISST ABS v1 0 19 Logging If you elec
12. 0 second wait should be done every time power is applied During these 30 seconds the LISST ABS is obtaining a running average of attenuation that is used internally to compute the ACB value that is output Shorter waits will result in noisier measurements It is also recommended that bursts of 30 measurements or more be recorded and averaged to obtain the best results Because of the small measurement volume of the LISST ABS the ACB measurements can vary sample to sample as clouds of turbidity pass by n order to obtain a representative value some averaging of these clouds should be done For example if measurements every 15 minutes are desired we recommend the following procedure 1 Power up the LISST ABS 45 seconds before the beginning of the desired sample time and allow it to sample 2 Issue the Start Measurement and Send Data commands to record 60 measurements 1 second apart 3 Power down the LISST ABS and wait till the next sample time For suggestions on mounting cleaning and maintenance please see Section 2 6 2 3 RS232 Output Operations RS232 Connections The LISST ABS has also been designed to support RS232 communication both transmit only and two way communication modes RS232 requires four wires Power Ground Transmit and Receive Appendix A includes detailed descriptions of the use of the individual pins of the 8 pin connector on the LISST ABS However in most cases you will be using a cable provided by
13. LISST ABS Acoustic Backscatter Sensor User s Manual Version 1 0 July 2015 SEQUOIA Sequoia Scientific Inc 2700 Richards Road Suite 107 Bellevue WA 98005 USA Phone 1 425 641 0944 Fax 1 425 643 0595 support SequoiaSci com www SequoiaSci com This page intentionally left blank FOR TECHNICAL ASSISTANCE please contact your local Distributor or Sequoia if the instrument was purchased directly from Sequoia Please be sure to include the instrument serial number with any correspondence A list of local Sequoia distributors can be found at our website http www sequoiasci com about contact distributors Sequoia Scientific Inc can be reached at support sequoiasci com or by phone 1 425 641 0944 Contents Ee 1 SECTION 2 INSTRUCTIONS 2 2 Orne 3 2 INTRODUCTION RH oh ler Lee 3 2 2 SDIET2 OPERATIONS s use tee 4 2 3 BS232 OUTP UT OPERATIONS ebbe Ede ee D 9 2 4 ANALOG OUTPUT 14 2 5 USB OPERATIONS VIA PC 16 2 6 FIELD DEPLOYMENT 23 APPENDIX A LISST ABS CABLE WIRING AND CONNECTOR
14. LITY OR FITNESS FOR A PARTICULAR PURPOSE AND ANY IMPLIED WARRANTY ARISING FROM COURSE OF PERFORMANCE COURSE OF DEALING OR USAGE OF TRADE OTHER THAN THOSE SPECIFICALLY SET FORTH IN PARAGRAPH 1 5 Exclusive Remedies CUSTOMER S RIGHTS AND REMEDIES SET FORTH IN PARAGRAPHS 2 AND 3 ABOVE ARE EXCLUSIVE AND IN LIEU OF ANY AND ALL OTHER RIGHTS AND REMEDIES FOR ANY BREACH OF OR OTHER FAILURE TO COMPLY WITH ANY WARRANTY WITH REGARD TO ANY PRODUCT 30 6 No Consequential Damages SEQUOIA will not be liable for any indirect incidental special or consequential damages any cover or any loss of revenue profit data or use 7 Limitations of Liability SEQUOIA s liability whether in contract tort or otherwise and notwithstanding any fault negligence strict liability or product liability with regard to any Product including but not limited to any breach of or default by SEQUOIA will in no event exceed the purchase price paid by Customer to SEQUOIA for such Product Further SEQUOIA will not be liable for or be in breach of or default on account of any delay or failure to perform as a result of any cause condition or circumstance beyond SEQUOIA s reasonable control 8 Indemnification by Customer Customer acknowledges that the Products are designed and manufactured for use in non critical monitoring situations If Customer chooses to purchase a Product or Products for use in applications that could result in damages in excess of the p
15. able you will need to provide power to the LISST ABS and connect the RS232 output to the PC to use the provided software You can now start the LISST ABS software to see the values in real time You can also use the software to store data Below is a screen shot of the software while collecting data More details on the operation of the software can be found in Section 2 5 a LISST ABS Attenuation Corrected Concentration Backscatter mg L Serial Number 4 890 gt 4 94 Sample Number 4 Raw Data Sample Interval 1 Sec Stop Loggin 30 Measurement Average 2997 Current File C Users TLeeuw Desktop ArizonaDust txt LISST ABS v1 0 Beta The value is a calibration value that is used to convert Attenuation Corrected Backscatter ACB to concentration in mg L You can determine your own value based on the type of particles you will be measuring The LISST ABS is calibrated and adjusted at the factory using 5 10 micron particles so that the Nrer for these particles will always be 1000 You may use this value for a quick approximation of concentration but proper calibration should be done to obtain the most accurate results More information about calibrating the LISST ABS and converting ACB to concentration can be found in Appendix B The ACB value will update at once per second as it receives data from the LISST ABS To store data to a file press the Create Log File button se
16. ain a representative value some averaging of these clouds should be done For example if measurements every 15 minutes are desired we recommend the following procedure 1 Power up the LISST ABS 45 seconds before the beginning of the desired sample time and allow it to sample 2 Record 60 measurements of the analog voltage 1 second apart 3 Power down the LISST ABS and wait till the next sample time For suggestions on mounting cleaning and maintenance please see Section 2 6 15 2 5 USB Operations PC software Installation USB Drivers The LISST ABS is shipped with a simple windows application that allows for viewing and logging of ACB data The application also provides a feature that allows for easy calibration of the LISST ABS The installer and related software files are located in the Software folder on your instruments ship disk Open the installer by double clicking on LISST ABS installer exe The software requires that you have windows NET framework 4 0 or later installed on your computer You can determine if the framework is installed on your computer by simply running the LISST ABS installer If the framework is missing a warning message will appear ie LISST ABS installer Installer Information AN Microsoft NET Framework 4 0 Client Package or greater needs to be installed For this installation to continue Should you receive this message return to the ship disk and run the dotNetFx40 Client
17. ar such as replacement of consumables nor for defects or failure caused by maintenance misuse negligence or failure resulting from non compliance with SEQUOIA s specifications operating or maintenance manuals 3 Infringement Indemnification If any Product does not comply with the warranty set forth in 1 c above SEQUOIA will defend and indemnify Customer against any third party claim asserted in any proceeding against Customer based on this noncompliance provided that Customer gives SEQUOIA prompt written notice of the claim SEQUOIA has exclusive control over the defense and settlement of the claim Customer provides such assistance as SEQUOIA may request in connection with the defense and settlement of the claim in which event SEQUOIA will reimburse the reasonable out of pocket costs incurred by Customer to provide such assistance Customer does not settle the claim without the prior written consent of SEQUOIA and upon SEQUOIA s request Customer returns the Non Complying Product to SEQUOIA for modification replacement or a refund of the purchase price paid by Customer to SEQUOIA for the Non Complying Product less a reasonable allowance for Customer s use prior to return 4 Exclusive Warranties THE WARRANTIES SET FORTH IN PARAGRAPH 1 ABOVE ARE EXCLUSIVE AND IN LIEU OF ALL OTHER WARRANTIES EXPRESS OR IMPLIED SEQUOIA DISCLAIMS ANY AND ALL WARRANTIES EXPRESS OR IMPLIED INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTY OF MERCHANTABI
18. atter pressure P at the transducer from a range ctis related to the outgoing pressure pulse the geometric spreading G R and attenuation by the combination of water and sediments It is helpful now to consider the signal via the sonar equation logio P Po G R 2 aw as R logio N R 1 This equation shows the weakening of the signal due to geometric spreading G R attenuation by absorption by water aw and sediment as and a noise floor N R The signal of interest is the scattering by particles o The LISST ABS actually measures the backscatter signal from two range cells located at and ct from the transducer so that it can compensate for attenuation by particles in water To understand consider the difference of two signals such as above but with assumption of equal concentration By difference we have logio P1 logio P2 AG R 2aw AR os AR 2 This shows that the difference in signals from two range bins is equal to the geometric spreading factor and attenuation The attenuation term is usually very small for LISST ABS until sediment concentration becomes high gt 19 L we ignore noise floor it is small Thus the two point backscatter determines the quantity in square bracket Any increase in the difference determines water attenuation term 27 Recalibration Knowing the terms in Eq 2 we simply project the measurement to a small distance from the transducer i e at 0
19. ediment Concentration Formula Recalibration The relationship between ACB and suspended concentration C is C 10 CB Nre 500 Where Nis characteristic of a sediment size and type All LISST ABS instruments are calibrated using natural particles between 5 and 10 microns They are configured so that N e 1000 for these particles This makes all LISST ABS sensor interchangeable Note that N eris the only variable that changes upon recalibration To compute concentration in Excel spread sheet insert the Formula as shown below with the value of Nret for your sediment 6 104 A5 C 5 B 5 NM gt ex 500 1000 0 01052 251 0 031769 1100 1 584893 2100 158 4893 Recalibration of the sensor for different size or type involves finding a new value for Recalibration can be done by using provided Windows software You will need to prepare a known concentration of your suspension in a very well mixed chamber Insert the instrument apply power The instrument displays ACB counts and Concentration at the previously held value of At any time Press the Recalibrate button and follow instructions At the end of about a minute the software computes the new Ne and loads it into the designated box The measurements that follow use this value of Nret to convert ACB counts to concentration in mg L This value is not saved on the instrument It
20. exe installer This will install the NET framework on your computer Once that is completed relaunch the LISST ABS installer exe and follow the installation instructions The installer will place a LISST ABS shortcut on your start menu as well as your desktop Before launching the LISST ABS software plug the USB cable into your computer If the computer has an internet connection it should automatically install the correct drivers A notification will appear on the screen if the drivers are being installed automatically If the drivers are not installed go back to the ship disk and run CDM USB Driver exe Follow the on screen instructions to install the drivers 16 Automatic Instrument Detection When the LISST ABS software is launched it will begin searching for the instrument on the ports of your computer Attenuation Corrected Concentration Backscatter g L Serial Number 6004 Searching For 4 Instrument E Create Log File Sample Interval 1 Sec V 30 Measurement Average Start Logging Current File LISST ABS v1 0 Ensure the instrument is connected to the computer via the USB cable Within a few seconds the software will find the instrument and begin displaying ACB values The instrument serial number will also be displayed at the center of the screen If the Sequoia USB cable is not available you can still use the software via any RS232 connection to the PC You will
21. here are also a set of commands that can be sent to the LISST ABS to give more control of the flow of data The available RS232 commands are described below The commands are not case sensitive and there are multiple command codes for the same command function Following the command descriptions are some suggested best practices for using the LISST ABS with RS232 LISST ABS RS 232 Command Summary Command Name Command Code Notes Display Status DS Status Display the Current Status of the instrument including instrument serial number and firmware version Take and Transmit Sample GS and hold GetSample Instrument makes a measurement stores itin temporary memory and outputs the results to the RS 232 output Take Sample and hold it HS Instrument makes a measurement and HoldSample stores it in temporary memory The results are NOT sent to the RS 232 output Transmit last sample SL Transmits the last sample collected by SendLast the issuing of a GS or HS command that was stored in temporary memory Return to Automatic Mode Return Returns the LISST ABS to automatic AutoMode mode where results are output to the Exit RS232 every 1 second Help HE Displays a list of commands available Help with brief descriptions See the next page for details of the RS232 commands LISST ABS RS232 Command Details Basic Command Set
22. in Eq 1 yielding the concentration term log o c With a little more arithmetic that is ACB In short the combined geometrical and water attenuation are measured once and are fixed Temperature related changes in are small and applied subsequently The sediment attenuation is measured by the change in the difference between two range cells And then the measurement is projected to the transducer to get ACB This is a simplified explanation The precise description of the computations is to be published separately Here we simply note that near field effect has been considered The relationship between ACB and sediment concentration is shown in the figure below for 5 10 micron AC dust Note that this is a log linear relationship ACB counts depend on log o C The slope of the calibration line Ko is fixed by electronics The offset at 1mg L where logio 1 20 is called For all instruments N er 21000 3500 3000 2500 2 2000 1500 1000 dig counts ACB 500 10 10 10 10 10 Concentration mg L A change in sediment grain size or other properties does not change Ko Only N eris recalibrated so that all sediment calibration lines are parallel To find the new calibration factor we recommend using our provided Windows software Prepare a mixture in a well mixed chamber Use of Sequoia s mixing chamber is strongly recommended Insert the instrument tip at the surface Be sure to leave 15 cm gap betwee
23. is only used in the Windows software Record this value in your notes for future reference For detailed instructions on using the LISST ABS software see Section 2 5 The Gold Standard values of all LISST ABS sensors is 1 000 These are factory set for standard 5 10 micron AC Dusts source Powder Technology Inc Arden Hills MN USA Conversion of a saved file of ACB s can be done using the formula above at any time even after a new Nrer is determined See Appendix C 26 Appendix How LISST ABS works Basics The LISST Acoustic Backscatter Sensor LISST ABS operates in a manner similar to radar A short pulse of high frequency sound is transmitted by a ceramic transducer see Figure ceramic transducer The pulse travels outward and its location at any time is at a distance equal to the product of speed of sound in water and time t after transmission ct Particles in the pulse called cell range cell range bin or sample volume scatter sound in all directions Some of this sound travels backward toward the transducer This scattered sound takes the same amount of time reach back to the transmitter This is the backscatter signal The total time for this signal out and back is 2t Thus the signal sensed at time 2t after pulse transmission corresponds to scattering from a range cell a distance ct from the transmitter This is the essence of acoustic backscatter The strength of the backsc
24. lect a location and name of a file to receive the data and then press Start Logging Data will be stored to the file until Stop Logging is pressed The log file contains a header with calibration constants the Nref values and the instrument serial number Following the header is a row for each sample containing date and time ACB and concentration The Log file is a space delimited ASCII file that can be easily imported into programs such as Excel The software has a provision to display a 30 second running average Select this option for a smoother display of ACB and Concentration This averaging is for the displayed value only The values saved to the Log file are not averaged Detailed instructions on connecting the LISST ABS to your datalogger are covered in separate sections of this manual For SDI 12 operations see Section 2 2 For Serial RS232 operations see Section 2 3 For Analog Output operations see Section 2 4 Section 2 Instructions 2 1 Introduction Thank you for your purchase of Sequoia s LISST ABS acoustic backscatter sensor The LISST ABS is a single point acoustic sediment sensor designed to provide higher quality data than optical turbidity sensors Its key advantages over optical turbidity sensors are e Superior response to particles of grain size 30 microns e Relatively flat sensitivity to particles from 30 400 microns in sizes e Greater immunity to fouling e Wide dynamic range of concentrations from 1mg L to
25. ltage 99 T __Recalibrate Recalibrate Nref Create Log File Sample Interval 1 Sec V 30 Measurement Average Start Logging Current File C Users Sequoia Desktop ABS_AzDust txt LISST ABS 110 Attenuation Corrected Concentration Backscatter mg L Serial Number 6004 Large object detected 1153 i m in sample volume parma Recalibrate Nref Create Log File Sample Interval 1 Sec 30 Measurement Average Current File Start Logging C Users Sequoia Desktop ABS_AzDust txt LISST ABS v1 0 22 2 6 Field Deployment Suggestions Mounting Orientation BioFouling reduction The mounting and orientation of the LISST ABS is similar to that of optical backscatter and turbidity sensor The suggestions below may help when determining how to mount or orientate the LISST ABS The LISST ABS measures backscatter from two cells at approximately 5 and 10 cm from the sensor head The two locations are used to measure the attenuation that is used in the internal computation of ACB For reduced drag mount the LISST ABS horizontally facing into a flow In this orientation it may be placed very close to a boundary e g a river bed limited only by considerations of bed scour The instrument may also be mounted vertically To avoid interference from bottom reflection the sensor head must be at least 15 cm above the hard bottom The computation of ACB assumes that the concen
26. n sensor and chamber bottom Press the Recalibrate button After completion in 1 minutes a new value will appear 28 Specifications Technical e Acoustic Frequency 8 MHz Sample Volume 10 dia x 15 L mm located 5 5 cm in front of sensor e Outputs 0 5 V analog e SDI 12 e RS232 e Range 1 mg L to 70 g L 7 um or 50 g L 200 um sand Calibration Recommended with in situ samples 22 00 50 8 Mechanical and Electrical Sensor Dia 2 00 in 5 08 cm Length 13 25 in 33 65 cm Weight 1 Ib 0 5 Kg in air 0 5 Ib 0 22Kg buoyant in water 10mm dia ceramic External supply 10 18 Vdc Current drain 100 mA Max Depth 100 m check with factory for deeper rating Material ABS Plastic Connector Impulse MCBH 8 MP SS Power on LED Green blink on update Sample update rate 1Hz average of 1000 measurements pings Warranty STATEMENT OF LIMITED WARRANTY AND LIABILITY This Statement of Limited Warranty applies to all Sequoia Scientific Inc SEQUOIA products Products Any additional or different terms including any terms in any purchase order will be of no effect unless agreed to in writing by an authorized representative of SEQUOIA as reflected in a written SEQUOIA quotation 1 Limited Warranty SEQUOIA warrants that upon delivery by SEQUOIA a the Products will be free from defects in materials and workmanship b the Products will perform substantially
27. need to power the instrument separately See Appendix A for wiring instructions Attenuation Corrected Concentration Backscatter g L Serial Number 6004 2943 Create Log File Sample Interval 1 Sec 1 30 Measurement Average Start Logging Current File LISST ABS 10 Should you have more than one ABS instrument plugged into your computer the software will interface with the first instrument it finds while searching your computers ports 17 Sampling Parameters Just below the Sequoia logo you have the ability to adjust the sample interval time between measurements and the option to apply a 30 measurement average Attenuation Corrected Concentration Backscatter g L Serial Number 6004 Recalibrate Nref Create Log File Sample Interval 1 Sec 30 Measurement Average Start Logging Current File LISST ABS v1 0 To change the sample interval simply type in the desired interval into the text box The interval must be in seconds must be a whole number and must be greater than or equal to 1 Changing this number will change how often the display is updated and how often data is logged see Logging covered below A checkbox allows you to apply a 30 measurement running average to the data This is for display only and has no effect on calibration or logging of data i e data are not averaged in the log file This can provide a more representative value with only
28. on When idle but still powered up it will do a single blink once per second 2 2 SDI 12 Operations SDI 12 Connections The LISST ABS has been designed to support SDI 12 protocol It is compatible with SDI 12 version 1 3 This section is divided into two parts Connecting to your datalogger and SDI 12 command summary SDI 12 only requires three wires Power Ground and Data Appendix A includes detailed descriptions of the use of the individual pins of the 8 pin connector on the LISST ABS However in most case you will be using a cable provided by Sequoia for connecting to your SDI 12 compatible datalogger To make the connections easier we have provided different cable terminations designed specifically for different connection requirements For example we provide a termination with only the three individual wires that are labeled and can be easily connected to the datalogger The mating connector makes it easy to remove the long cable without disconnecting the wires from the datalogger You can also easily switch between the datalogger and the USB cable if needed The wires are labeled and color coded Connect the Black wire to Ground Connect the Red wire to 12V Connect the Green wire to SDI 12 Data The LISST ABS is shipped pre configured with an instrument address of 0 The available SDI 12 commands are described below Following the command descriptions are some suggested best practices for using the LISST ABS with SDI 12
29. rice of the Product if the Product does not operate properly or otherwise fails Customer acknowledges and agrees that it is Customer s responsibility to provide for redundancy and or other safety or back up measures sufficient to assure that failure of a Product s will not cause such damages Customer agrees that it will defend and hold SEQUOIA harmless from any and all claims and costs including but not limited to attorney s fees and other costs of defense against such claims in excess of the price of the Products arising directly or indirectly from such Customer s use of the Products Such indemnification is a critical part of the consideration being provided by Customer over and above the price paid for the Product s for the right to use the Products for such purposes and Customer shall not use a Product or Products for such purposes if it is unwilling or unable to provide such indemnification 9 Statute of Limitations Customer will not commence any action based on breach of warranty with respect to any Product more than 30 months after SEQUOIA s delivery of such Product 10 Software The Products may include or be delivered with certain computer programs databases or other software that is proprietary to SEQUOIA SEQUOIA hereby grants Customer a nonexclusive license to use such software solely for the purpose of operating Products Customer will not use any such software for any other purpose modify adapt translate or create derivative
30. ring Sequoia offers cables for the LISST ABS in lengths from 5 to 50 meters _ These cables include an underwater connector is spliced to a longer cable which is terminated with a white plastic Molex connector When purchasing the long cable multiple mating cables are provided for different datalogger connections There are pigtail ends for SDI 12 connections RS232 connections Analog Output connections and a USB Cable for use with a PC The table below shows the details of the wiring of the different cables Sequoia lon RS232 DI 12 Anal MEENEMEN ABS eae pigtail a Wire Wire Wire Wire Wire Pin Function color color color color color 1 Common Black White Black Black Black 2 V 10 to 18V White Red Red Red Red 3 Common Red 4 RS232 transmit Green Yellow Yellow 5 RS232 receive Blue Blue Blue 6 SDI 12 data Grey Black Green 7 Analog out Yellow Green 8 shield White The long cable is terminated with a Molex Mini Fit Jr Female connector Molex 0039012081 with Molex 0039000431 pins The mating pigtail cables use a male connector with a latch Molex 0039012080 with Molex 80039000073 sockets Both connector have labels for the pin numbering molded into the plastic body of the connector The pin number is also shown above 25 Appendix B Converting ACB Data to S
31. tax HE or help Description Displays a list of commands available with brief descriptions Example Command help Response LISST ABS help menu DS or Status Display status GS or GetSample Take a sample and return the ACB HE or Help This menu HS or HoldSample Take a sample and hold the ACB nothing returned AutoMode Exit Return to 1hz sampling Press lt cr gt three times to or Return halt sampling SL or ShowLast Display the previous sample taken by GS or HS Commands are not case sensitive LISST ABS gt LISST ABS and RS232 Best practices In order to obtain the most accurate results it is recommended that the LISST ABS be powered up and allowed to sample in the automatic mode green LED double blinking for 30 seconds or more before issuing a Start Measurement command This 30 second wait should be done every time power is applied During these 30 seconds the LISST ABS is obtaining a running average of attenuation that is used internally to compute the ACB value that is output Shorter waits will result in noisier measurements It is also recommended that bursts of 30 measurements or more be recorded and averaged to obtain the best results Because of the small measurement volume of the LISST ABS the ACB measurements can be vary sample to sample as clouds of turbidity pass by In order to obtain a representative value some averaging of these clouds should be done For example if measurements
32. ted to save the raw ACB values a text file will be saved at the location you specified before starting the calibration It will contain a header with calibration information followed by the 100 ACB measurements used to calculate the new File Edit Format View Help KO 500 Nref 1153 Calibration concentration mg L 3000 Calibration Date 07 28 2015 08 56 46 Calibration Comments 5 10 Micron Arizona Dust SN 6004 2897 2888 2912 2887 Should you need to remind yourself where an Nret value came from you can click the info button located next to the textbox det 1 Nref 1153 WL Date 07 28 2015 08 56 46 Comments 5 10 Micron Arizona Dust Sec 4 30 Measurement Average Start Logging LISST ABS v1 0 Before data can be saved a log file must be created Start by clicking on the Create Log File button A browser will open that will allow you to specify a location and name for the log file Once that is complete the location of the log file will be displayed at the bottom of the screen note the location displayed at the bottom of the screen can also be edited by hand which is handy for incrementing file names 20 Errors Disconnection Press the start logging button to begin saving data to the log file The number of measurements saved to the log file will be displayed in the lower right of the screen Attenuation Corrected Concentration Backscatter mg L Serial Number 6004
33. to confirm it is active Response O responds with address of sensor Change Address Syntax aAb Description Change address of sensor at address ato b Example Command 0A3 request sensor at address 0 to change to address 3 Response 3 responds with new address of sensor al Send Identification Syntax al Description Send ID string including SI address SDI version Manufacturers ID sensor model sensor Firmware version and device serial number Example Command 3I request sensor at address 3 to send ID string Response 313SequoiaSABS001001 123456 Where Sensor address 1 character 13 SDI Version compatibility 2 characters SequoiaS Manufacturers ID 8 characters 5001 Sensor Model 6 characters 001 Sensor Firmware 3 characters 123456 Sensor Serial Number 6 characters Start Measurement Syntax aM Description Start a measurement returns number of seconds till sample is ready to be read Sends service request when measurement is complete Example Command 3M request sensor at address 3 to make as measurement Response 30011 3 is the address 001 is of seconds 1 is the of values after 1 second gt 3 sends address to confirm measurement is ready to be read Start Concurrent Measurement Syntax Description Start a measurement returns number of seconds till sample is ready to be
34. to dataloggers with screw terminals There are separate pigtails for SDI 12 RS232 and Analog Output connections Also included is a credit card style USB memory card with software installation files The sensor head is covered with a protective red cap to prevent accidental impact and damage of the acoustic transceiver white disc Be sure to remove the protective cap before use The instrument will not work with the cap left on The underwater connector is also covered with a protective cap A simple program that can be used for testing the LISST ABS is included on the USB memory card To install the software on your computer run the LISST ABS installer exe program on the memory card This will install the LISST ABS software This software requires the NET 4 0 Framework Most computers will have this framework already installed as it is used by many other programs A message will appear if the NET 4 0 needs to be installed You can install NET using the dotNetFx40 Client exe program on the memory card The LISST ABS is a sensor only and must be connected to a power source We have designed a USB cable to provide power and communicate with the instrument via one connection to a PC Connect the long cable to the LISST ABS and then plug in the USB cable into the PC You should see the green LED on the LISST ABS start to blink Every time the LISST ABS blinks data is being sent up the cable to the PC If the LISST ABS was purchased without a c
35. tration is similar between the range cells If there is a strong vertical gradient causing significant differences between them the ACB will not be accurate The sensor housing is made of plastic DO NOT apply excessive force while mounting The diameter of the main is just under 2 inches There are many different types of clamps available for this diameter Biofouling can be a problem for any sensor deployed in the water Even though the LISST ABS is more tolerant to biofouling it is still recommended to use some anti fouling procedures to reduce the chance of fouling effecting the measurements Do not apply anti fouling paint directly to the transducer face as it will affect the instrument performance 23 Appendix A LISS TABS Cable Wiring and Connector Pinouts This appendix details the configuration of the LISST ABS connectors and cables so that it can be connected to the dataloggers We will start at connector on the LISST ABS and work toward the end of the long cable Details of The endcap connector on the LISST ABS is an Impulse MCBH8 M P wired Underwater shown below Mating connector is MCIL8 F S connector on LISST ABS Common Supply voltage 10 to 18 V Common RS232 transmit RS232 receive SDI 12 input output Analog output Common oxooROM The Common pins are interchangeable and connected to each other inside the ABS Bulkhead Connector numbering Cable Connector Numbe
36. works based on any such software or disassemble decompile or reverse engineer any such software No title to or ownership of any software or intellectual property rights are transferred to Customer 11 U S Government Restricted Rights Notice All software data technical information and written materials provided by SEQUOIA are provided with restricted rights Use duplication or disclosure by the government is subject to restrictions as set forth in subparagraph c 1 ii of the Rights in Technical Data and Computer Software clause at 48 C F R 252 227 7013 or in subparagraph c 2 of the Commercial Computer Software Restricted Rights clause at 48 C F R 52 227 19 as applicable Portions of these items may be unpublished SEQUOIA reserves all rights under applicable copyright laws 12 Controlling Document In the event of any conflict or inconsistency between any provision of this Statement of Limited Warranty and any other provision of the Order the provision of this Statement of Limited Warranty will control 13 Controlling Law This Statement of Limited Warranty will be governed by the laws of the State of Washington without reference to its rules relating to choice of law for the purpose of applying another jurisdiction s law The U N Convention on Contracts for the International Sale of Goods will not apply 31
37. y the four individual wires that are labeled and can be easily connected to the datalogger The mating connector makes it easy to remove the long cable without disconnecting the wires from the datalogger You can also easily switch between the datalogger and the USB cable if needed The wires are labeled and color coded Connect the Black wire to Power Ground Connect the Red wire to 12V Connect the Green wire to Analog input and the White wire to the Signal Ground The Analog Output of the LISST ABS is configured such that 1mv of output is equal to 1 ACB count Therefore if the output of the LISST ABS is 1234 ACB counts then the analog voltage would be set to 1234 mV or 1 234 volts In order to obtain most accurate results it is recommended that the LISST ABS be powered up and allowed to sample in the automatic mode green LED double blinking for 30 seconds or more before recording the analog voltage output This 30 second wait should be done every time power is applied During these 30 seconds the LISST ABS is obtaining a running average of attenuation that is used internally to compute the ACB value that is output Shorter waits will result in noisier measurements It is also recommended that bursts of 30 measurements or more be recorded and averaged to obtain the best results Because of the small measurement volume of the LISST ABS the ACB measurements can be vary sample to sample as clouds of turbidity pass by In order to obt
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