Home

OBS500 Smart Turbidity Meter with ClearSensor™ Technology

1. Table 7 9 Calibration Materials and Volumes Calibration Cup Diameter Sidescatter 90 Degree Materials mm inches 8594 20TU 100 4 8595 40TU 100 4 8596 125TU 100 4 8597 250TU 100 4 8598 SOOTU 100 4 8599 1000TU 100 4 OBS Sensor Material 8600 125TU 200 7 9 8601 250TU 200 7 9 8602 500TU 200 7 9 8603 1000TU 100 4 8604 2000TU 100 4 8605 4000TU 100 4 The GFS item numbers standard values and volumes required for the standard low ranges are given in Table 7 9 SDVB standards have a shelf life of two years provided that they are stored in tightly sealed containers and evaporation is minimized 23 OBS500 Smart Turbidity Meter with ClearSensor Technology 24 The TU values of the standards will remain the same as long as the ratio of particle mass number of particles to water mass volume does not change Evaporation causes this ratio to increase and dust bacteria growth and dirty glassware can also cause it to increase Therefore take the following precautions 1 Always use clean glassware and calibration containers 2 Don t leave standards on the bench in open containers or leave the standard bottles uncapped Perform the calibration as quickly as possible and return the AMCO solutions to their bottles 3 Clean dirty sensors with a clean alcohol soaked cloth to sterilize them before dipping them into the standard
2. Send File Figure 7 2 Terminal Mode using 1 and H commands Table 7 2 RS 232 Terminal Commands Terminal Commands Values Returned 1 Identify 2 Open Wiper 3 Close Wiper Serial Number SDI 12 address etc Command to open wiper started please wait Wiper now open average current was xxx mA Command to close wiper started please wait Wiper now closed average current was xxx mA User Manual DevConfig allows you to change the configuration of the OBS500 Select the Settings Editor tab Device Configuration Utility 2 00 elel E File Options Help Dore Settings Editor AVW200 Series CCSMPX CC640 Send OS Terminal Current Setting CD295 COM220 Address COM320 o E CR1000 CR10X CR10X PB CR10X 1D CR200 Series CR23X IE OS Version CR5000 CRS10 CR510 PB CRS10 TD 1200 m CR800 Series CR9000X CS1 CS450 CS650 Series CWB100 CWS220 CWS655 CWS900 EC100 MD485 NL100 PS200 CH200 RF400 OBS500 Std 00 11 0xf764 OBS500 measurement mode Side scatter ratio top RF401 RF430 RF450 RFSOOM PC Serial Port COM1 Baud Rate 9600 OBS500 measurement mode Specifies measurement 0 SDI12 or R 232 1 Analog Cancel Factory Defaults ReadFile Summary NOTE Figure 7 3 Settings Editor screen There are three settings that can be changed
3. CR5 extension for CR200 X CR1000 CR800 CR3000 or CR5000 dataloggers respectively Select the file and click Open Immediately save the file in a folder different from Campbellsci SCWin or save the file with a different file name Once the file is edited with CRBasic Editor Short Cut can no longer be used to edit the datalogger program Change the name of the program file or move it or Short Cut may overwrite it next time it is used The program can now be edited saved and sent to the datalogger Import wiring information to the program by opening the associated DEF file Copy and paste the section beginning with heading Wiring for CRXXX into the CRBasic program usually at the head of the file After Appendix A Importing Short Cut Code A 1 2 Edlog NOTE pasting edit the information such that a character single quotation mark begins each line This character instructs the datalogger compiler to ignore the line when compiling the datalogger code Use the following procedure to import Short Cut code into the Edlog program editor CR10 X CR500 CR510 and CR23X dataloggers 1 Create the Short Cut program following the procedure in Section 4 Quickstart Finish the program and exit Short Cut Make note of the file name used when saving the Short Cut program Open Edlog Click File Document DLD File Assuming the default paths were used when Short Cut was installed navigate to C Campbell
4. OBS sensors detect IR backscattered between 90 and 165 where the scattering intensities are nearly constant with the scattering angle Particle concentration has the most significant effect in this region OBS sensors are more sensitive by factors of four to six to mineral particles than particulate organic matter and interference from these materials can therefore be ignored most of the time One notable exception is where biological productivity is high and sediment production from rivers and re suspension is low In such an environment OBS signals can come predominately from plankton User Manual 9 Maintenance WARNING WARNING There is a biocide chamber in the slider that is refillable The default biocide from the factory is copper braid The braid will last for many years but it can be replaced as desired Other solid biocides can be placed in the chamber To be effective over time the biocide should be slow to dissolve The OBS500 should be sent in for service seal shaft and nut replacement after 2 years or 70 000 cycles of the shutter whichever occurs first The sensor has a cycle count and a moisture alarm in the data string SDI 12 and RS 232 only If the seals are not replaced the sensor will eventually leak and potentially be destroyed It is recommended that the cycles and moisture alarm be recorded regularly If a moisture alarm is recorded the sensor shutter should be parked and the sensor taken out of the
5. Public Open Declare Other Variables Alias 0BS500 1 turb_bs Alias 0BS500 2 turb_ss Alias 0BS500 3 tempC_obs500 Alias 0BS500 4 wet dry Alias obsDatOpen 1 Open_counts Full movement of slider is about 20 000 counts If it jams this will be smaller Alias obsDatOpen 2 Open_Max_mA_cnts Number of times the shutter stops while opening because of max current Alias obsDatOpen 3 Open_slip Open timeout count If the threads are stripped the slide will not move and this count will increase Alias obsDatOpen 4 Open_mA mA current of the motor Alias obsDatClose 1 Close_counts Full movement of slider is about 20 000 counts If it jams this will be smaller Alias obsDatClose 2 Close Max mA cnts Number of times the shutter stops while opening because of max current Alias obsDatClose 3 Close_slip Open timeout count If the threads are stripped the slide will not move and this count will increase Alias obsDatClose 4 Close_mA mA current of the motor Units turb_bs fbu Units turb_ss fnu Units tempC_obs508 degC Units wet_dry YesNo Define Data Tables DataTable Test 1 1000 DataInterval 0 5 Min 10 Sample 1 turb_bs FP2 Sample 1 turb_ss FP2 EndTable Main Program BeginProg Scan 60 Sec If open make measurement and close If closed open then make measurement If Open 1 Then If open the make measurement then close SDI12Recorder 0BS500 1 0 M4 1 0 Measure without moving the
6. Quiescent Current Measurement Communication Current Shutter Motor Active Current Maximum Peak Current Cycle Time Measurement Time Outputs Submersion Depth Diameter Length Weight Maximum Cable Length Shutter wiper biocide copper optional removable sleeve 0 5 TU or 42 of reading whichever is greater 0 3 C 0 to 40 C 0 to 40 C non freezing ice may destroy the sensor 0 to 45 C 850 nm 9 6 to 18 Vdc lt 200 pA lt 40 mA lt 120mA 200 mA for 50 ms when shutter motor starts Open measure close lt 25 s lt 2s SDI 12 version 1 3 1200 bps RS 232 9600 bps 8 data bits 1 stop bit no parity no flow control Analogue 0 to 5 Volts 100 m 328 ft 4 76 cm 1 875 in 27 cm 10 625 in 0 52 kg 1 15 Ib 460 m 1500 ft 1 channel SDI 12 or Analogue 15 m 50 ft RS 232 If you are programming your datalogger with Short Cut skip Section 7 3 Datalogger RTU Connection and Section 7 6 Programming Short Cut does this work for you See Section 4 Quickstart for a Short Cut tutorial Default Settings The OBS500 is configured at the factory with the default settings shown in Table 7 1 For most applications the default settings are used User Manual Table 7 1 Factory Settings SDI 12 Analogue SDI 12 RS 232 Baud Rate 7 2 Device Configuration Utility The Device Configuration Utility DevConfig is used to change settings set up the analogue senso
7. TAL SDE RR EE EG Ee AA el epee eens Se ed eg 17 TAAL SDI 12Addresses iese se se ee Re aen ee ee ee 20 7 4 1 2 SDI 12 Transparent Mode iese see see se ee ee ee ee ee 20 TA RSA 2 2 us A A el ee Re ee 22 1 9 Vi AE OE la Guia ER atri 22 RAN EE EER N EE HERE HE OR EE EN eiis 22 N El n RR EE EE EE OR ee ER ER iik 26 7 52 1 Dry Sediment Calibration se see ee ee se ee ee ee 26 7 5 22 Wet Sediment Calibration i 26 7 5 2 3 In situ Calibration i 27 1 5 2 4 Performing a Dry Sediment Calibration 27 1 6 PLOSTAMMUNG EE ARE EE O 28 AMIA NA AUREA 28 7 6 2 CRBasic Programming nono nccn nono corno 28 7 6 2 1 SDI 12 Programming se see se es ee ee ee Ge ee ee ee 28 1 62 2 RS 232 PrXgamMiNB nennen 29 7 6 2 3 Analogue Programming sesse se ee ee ee Ge ee ee ee 29 7 6 3 Edlog Programming uu cece see se ee ee ee Ge Se Ge Re Se RA ed ee ee 29 7 7 Operation in High Sediment Loads and Sandy Sediments 29 7 1 1 Wiper Removal Procedure i 30 8 Factors that Affect Turbidity and Suspended Sediment Measurements u meine O2 8 1 Particle SIZE ii a 32 8 2 Suspensions with Mud and Sand en 33 8 3 Particle Shape Effects 34 8 4 High Sediment Concentrations see se ee ee ee ee Se Ge ke Se ke ee 34 8 5 IR Reflectivity Sediment Colour
8. e Use only manufacturer recommended parts materials and tools Utility and Electrical e You can be killed or sustain serious bodily injury if the tripod tower or attachments you are installing constructing using or maintaining or a tool stake or anchor come in contact with overhead or underground utility lines e Maintain a distance of at least one and one half times structure height or 20 feet or the distance required by applicable law whichever is greater between overhead utility lines and the structure tripod tower attachments or tools e Prior to performing site or installation work inform all utility companies and have all underground utilities marked e Comply with all electrical codes Electrical equipment and related grounding devices should be installed by a licensed and qualified electrician Elevated Work and Weather e Exercise extreme caution when performing elevated work e Use appropriate equipment and safety practices e During installation and maintenance keep tower and tripod sites clear of un trained or non essential personnel Take precautions to prevent elevated tools and objects from dropping e Do not perform any work in inclement weather including wind rain snow lightning etc Maintenance e Periodically at least yearly check for wear and damage including corrosion stress cracks frayed cables loose cable clamps cable tightness etc and take necessary corrective actions e Periodically a
9. for an example of using this CRBasic instruction 7 6 2 2 RS 232 Programming The SerialOut instruction sends strings over the Tx COM port and the SerialIn instruction receives strings from the Rx COM port Refer to Appendix B 2 CR1000 RS 232 Program for an example of using these CRBasic instructions 7 6 2 3 Analogue Programming The PortSet instruction is used to open the shutter Either the VoltDiff recommended or VoltSe instruction is used to measure the analogue voltage output Refer to Appendix B 2 CR1000 RS 232 Program for an example of using these CRBasic instructions 7 6 3 Edlog Programming Our CR500 CR510 CR10 X and CR23X dataloggers are programmed with Edlog These dataloggers use Instruction 105 SDI12Recorder to read the OBS500 Your datalogger manual has a detailed explanation of Instruction 105 Note that Edlog only allocates one input location for Instruction 105 Two input locations are required one for the pressure measurement and one for the temperature measurement The additional input location needs to be inserted manually using the Input Location Editor To get into the Input Location Editor select Edit Input Labels or press the F5 key Once in the Input Location Editor do the following steps 1 Choose Edit Insert Block 2 After the Insert Block dialog box appears type in a base name for the input locations Each input location will have the base name with an underscore and a consec
10. Area lin square inch 645 mm Mass 1 oz ounce 28 35 g 1 Ib pound weight 0 454 kg Length 1 in inch 25 4 mm 1 ft foot 304 8 mm Pressure 1 psi Ib in 68 95 mb 1 yard 0 914 m 1 mile 1 609 km Volume 1 UK pint 568 3 ml 1 UK gallon 4 546 litres 1 US gallon 3 785 litres In addition while most of the information in the manual is correct for all countries certain information is specific to the North American market and so may not be applicable to European users Differences include the U S standard external power supply details where some information for example the AC transformer input voltage will not be applicable for British European use Please note however that when a power supply adapter is ordered it will be suitable for use in your country Reference to some radio transmitters digital cell phones and aerials may also not be applicable according to your locality Some brackets shields and enclosure options including wiring are not sold as standard items in the European market in some cases alternatives are offered Details of the alternatives will be covered in separate manuals Part numbers prefixed with a symbol are special order parts for use with non EU variants or for special installations Please quote the full part number with the when ordering Recycling information At the end of this product s life it should not be put in commercial or domestic refuse but sent for
11. NextScan EndProg Appendix B Example Programs B 4 Examples for High Sediment Loads B 4 1 Normally Open CR1000 Example CR1000 Series Datalogger 0BS500 normally open In normally open mode the 0BS500 can make measurement multiple times per minute but the wiper interval could be set to as low as a time or two a day This mode is also beneficial where the power budget is critical since opening and closing the wiper consumes considerably more power than making the turbidity measurement Declare Public Variables Public 0BS500 4 Public TimeCounter Public obsDatOpen 4 obsDatClose 4 Declare Other Variables ias 0BS500 1 turb_bs ias 0BS500 2 turb ss ias 0BS500 3 tempC_obs5e0 ias 0BS500 4 wet dry ias obsDatOpen 1 Open_counts Full movement of slider is about 20 000 counts If it jams this will be smaller ias obsDatOpen 2 Open_Max_mA_cnts Number of times the shutter stops while opening because of max current ias obsDatOpen 3 Open slip Open timeout count If the threads are stripped the slide will not move and this count will increase ias obsDatOpen 4 Open_mA mA current of the motor ias obsDatClose 1 Close_counts Full movement of slider is about 20 000 counts If it jams this will be smaller ias obsDatClose 2 Close Max_mA_cnts Number of times the shutter stops while opening because of max current ias obsDatClose 3 Close slip Open timeout count If the threads are stripped
12. measured every scan These can be changed by clicking the Temperature or Measure Sensor box and selecting a different option Typically the default SDI 12 address of 0 is used O POT CAMI Cart SEWE Eed sca Scan Iverat 3 0000 re Avalable Sensors and Dences proa E 1009 1 New Open 2 Sensors lt 2 Datalogger 4 Canenc Meliurements TA Geotechmcal A Structural 3 Sensors 4 Outputs ly Cakulations A Control Ca Calcutatione GE EE J 247 247 W Conductivity and Temperature Probe L 05510 Dissolved Oxygen Probe 05511 Dessolved Oxygen Probe 1 03512 Dissolved Oxygen Probe J 05525 ISFET pH Probe 05526 ESET pit Probe J CS547A Conductivity and Temperature Probe CS BAL1 ORP Probe 151 M11 ORP J CSIM11 pH Probe 151 M11 pm J tr Stu Mat Parameter TROLL 000 J 085 3 Tutedty Monitor J 085 3 085300 Turtidty Sensor 085500 Smart Turbidity Mater 501 12 KEN J Offset Cateuanon J SDI 12 Matigecbe 095509 Smart Turtadity Mater Thes sensor fila wil configure thal temperature measurement and Backscatter Turbidity units are Sidescatter Turtety units are FAN Temperature units are Deg C D Selected Sensor Measurement R1000 Detmat Batty Premp_c Backscatter Turtedity Tub_B5 fou Ddescatter Tuetidity TED SS mu Temperature Toc mes 501 12 Address 0 9 A Z or a 2 0 lt Maasure sensor Every Scan la 085509 Smart Turtadity Mater SDI 12 Tres sentor
13. product is out of the guarantee period it should be accompanied by a purchase order Quotations for repairs can be given on request It is the policy of Campbell Scientific to protect the health of its employees and provide a safe working environment in support of this policy a Declaration of Hazardous Material and Decontamination form will be issued for completion When returning equipment the Repair Reference Number must be clearly marked on the outside of the package Complete the Declaration of Hazardous Material and Decontamination form and ensure a completed copy is returned with your goods Please note your Repair may not be processed if you do not include a copy of this form and Campbell Scientific Ltd reserves the right to return goods at the customers expense Note that goods sent air freight are subject to Customs clearance fees which Campbell Scientific will charge to customers In many cases these charges are greater than the cost of the repair x CAMPBELL SCIENTIFIC Campbell Scientific Ltd 80 Hathern Road Shepshed Loughborough LE12 9GX UK Tel 44 0 1509 601141 Fax 44 0 1509 601091 Email support campbellsci co uk www campbellsci co uk PLEASE READ FIRST About this manual Please note that this manual was originally produced by Campbell Scientific Inc primarily for the North American market Some spellings weights and measures may reflect this origin Some useful conversion factors
14. recycling Any batteries contained within the product or used during the products life should be removed from the product and also be sent to an appropriate recycling facility Campbell Scientific Ltd can advise on the recycling of the equipment and in some cases arrange collection and the correct disposal of it although charges may apply for some items or territories For further advice or support please contact Campbell Scientific Ltd or your local agent fz CAMPBELL Ly SCIENTIFIC Campbell Scientific Ltd Campbell Park 80 Hathern Road Shepshed Loughborough LE12 9GX UK Tel 44 0 1509 601141 Fax 44 0 1509 601091 Email support campbellsci co uk www campbellsci co uk Precautions DANGER MANY HAZARDS ARE ASSOCIATED WITH INSTALLING USING MAINTAINING AND WORKING ON OR AROUND TRIPODS TOWERS AND ANY ATTACHMENTS TO TRIPODS AND TOWERS SUCH AS SENSORS CROSSARMS ENCLOSURES ANTENNAS ETC FAILURE TO PROPERLY AND COMPLETELY ASSEMBLE INSTALL OPERATE USE AND MAINTAIN TRIPODS TOWERS AND ATTACHMENTS AND FAILURE TO HEED WARNINGS INCREASES THE RISK OF DEATH ACCIDENT SERIOUS INJURY PROPERTY DAMAGE AND PRODUCT FAILURE TAKE ALL REASONABLE PRECAUTIONS TO AVOID THESE HAZARDS CHECK WITH YOUR ORGANIZATION S SAFETY COORDINATOR OR POLICY FOR PROCEDURES AND REQUIRED PROTECTIVE EQUIPMENT PRIOR TO PERFORMING ANY WORK Use tripods towers and attachments to tripods and towers only for purposes for which they are designed
15. the slide will not move and this count will increase ias obsDatClose 4 Close_mA mA current of the motor BpPBPBEPBPpBPBPBB gt BB Units turb_bs fbu Units turb_ss fnu Units tempC_obs508 degC Units wet_dry YesNo Define Data Tables DataTable Test 1 1000 DataInterval 0 5 Min 10 Sample 1 turb_bs FP2 Sample 1 turb_ss FP2 EndTable Main Program BeginProg SDI12Recorder obsDatOpen 1 0 M3 1 0 Start with shutter open Scan 1 Min 0 0 TimeCounter TimeCounter 1 Wipe at a slower interval than the scan interval If TimeCounter gt 60 Then This value 60 will wipe once every 60 scan intervals 60 minutes in this case SDI12Recorder obsDatClose 1 0 M7 1 0 SDI12Recorder obsDatOpen 1 0 M3 1 0 TimeCounter EndIf Read 0BS500 each scan interval SDI12Recorder 0BS500 1 0 M4 1 0 Measure without moving the wiper Call Output Tables CallTable Test NextScan EndProg Appendix B Example Programs B 4 2 Cycle Shutter Wiper for Each Measurement CR1000 Program The following CRBasic program will e Open the shutter if closed then make a measurement e Make a measurement if open then close Shutter wiper cycles will be cut by 50 This will reduce wear and power consumption 50 but still leave the optics shuttered 50 of the time CR1000 Series Datalogger 0BS500 cycle shutter each measurement Declare Public Variables Public 0BS500 4 Public obsDatOpen 4 obsDatClose 4
16. water and returned for repair as soon as possible Other than the sleeve and the biocide chamber on the sensor tip there are no user serviceable parts inside the sensor housing Do not remove the sensor or connector from the pressure housing This will void the warranty and could cause a leak Plastic pn 27473 and copper pn 27803 sleeves are available for the OBS500 to reduce required cleaning The plastic sleeve is intended to be disposable The copper sleeve should slow fouling growth but it may need to be cleaned If the sleeve becomes encrusted with organisms such as barnacles or tube worms remove the sleeve The sleeve can be soaked in weak acids or other cleaning products that are compatible with copper The sleeve may have to be gently scraped with a flexible knife blade followed by a ScotchBrite scouring pad Do not use solvents such as MEK Toluene Acetone or trichloroethylene on OBS sensors Downloading a New Operating System DevConfig is used to download a new operating system to the OBS500 Select the Send OS tab and follow the directions on the screen 37 OBS500 Smart Turbidity Meter with ClearSensor Technology non i N File Options Help Device Type AVW200 Series CCSMPX CC640 CD295 COM220 COM320 CR1000 CR10X CR10X PB CR10X TD CR200 Series CR23X CR23X PB CR23X TD CR3000 CR5000 CR510 CR510 PB CR510 TD CR800 Series CR9000X CS120 CS450 CS650 Series CWB 100 CWS220 CWS65
17. 0 CR1000 and CR3000 dataloggers have COM ports control port Tx Rx pairs that can be used to measure RS 232 sensors Both the C and U terminals can be configured as Tx Rx pairs for measuring RS 232 sensors 16 User Manual Table 7 5 RS 232 Wiring RS 232 9 pin Colour OBS500 Connection Datalogger Control Port Function Red 12VDC Power Source Black Power Ground Power Ground RS 232 Tx 3 Pin 2 Rx Input wine Output Transmit Control Port Rx RS 232 Rx Pin 3 Tx Output Blue Input Receiye Control Port Tx Brown Green Clear Shield GND Ground 7 3 3 Analogue 0 to 5 Volt Wiring Table 7 6 Analogue 0 5 Volt Wiring CR6 CR800 CR850 CR1000 CR3000 CR5000 Colour Description CR23X CR10X Backscatter Low or Green Sienal Differential High or 5 Single Ended Input Differential Low or ocu Saum Analogue Ground Power Ground Red Power SW12V The measurement sequence is to raise the blue wire from ground to 5 volts to open the shutter delay 6 seconds and then measure the backscatter analogue output on the green wire If sidescatter is desired then raise the white wire from ground to 5 volts delay 3 seconds and then measure the sidescatter analogue output on the green wire In either case lower the blue wire to ground to close the shutter Note that measurements can be differential or single ended Differential measurements are recommended The output is scaled as 1 mV
18. 1 Section 7 5 1 Turbidity mount the OBS500 so that the sensor end is 50 mm above the bottom of the suspender tub and secure it in the position that minimizes reflections from the wall see Figure 7 8 Figure 7 8 Portable Sediment Suspender left and OBS beam orientation in suspender tub right SSC Wts Vw Wts ps where Wts total sediment weight in tub in mg Vw volume of water in litres p density of water p 1 0 kg L at 10 C and ps sediment density assume 2 65 10 mg L 27 OBS500 Smart Turbidity Meter with ClearSensor Technology 28 Procedure 1 Record and log the clean water signal as in Step 1 Section 7 5 1 Turbidity see Figure 7 6 Use the same value such as sidescatter backscatter or ratio throughout the calibration Move the OBS500 to the suspender as described in setup Weigh 500 10 mg of sediment in a weigh boat and transfer it to the teacup Record the weight on the calibration log sheet and add about 10 cc of water from the suspender tub to the teacup and mix the water and sediment into a smooth slurry with the teaspoon Add the sediment slurry to the tub and rinse the teacup and spoon with tub water to get all the material into the suspender Turn the suspender on and let it run for 10 minutes or until the OBS signal stabilizes Take averages of signals with the computer or datalogger and enter them on the calibration log sheet Calculate the sediment weight increm
19. 5 CWS900 EC100 MD485 NL100 PS200 CH200 RF400 RF401 RF430 RF450 RF500M Disconnect Send OS OBS500 OS Download Instructions Using this panel you can download a new operating system into an OBS500 sensor In order to download an operating system to the probe power 12 Volts DC must be available for the sensor You must also have a serial link to the sensor This is most easily done by using the OBS500 test cable When the sensor is connected as described above turn off the power to the sensor click on the start button below A dialogue box will appear that will allow you to select the file that is to be sent as an operating system After you have selected a file and pressed OK in that dialogue restore power to the probe Once the initial synchronization takes place between this program and the sensor the operating system will be sent to the OBS500 Sent 417 of 1786 fragments Figure 9 1 DevConfig Send OS 10 Troubleshooting 38 A common cause for erroneous turbidity sensor data is poor sensor connections to the datalogger Problem Unit will not respond when attempting serial communications Suggestion Check the power Red is V and Black is Ground and signal White is SDI 12 Data lines to ensure proper connection to the datalogger Check the datalogger program to ensure that the same port the SDI 12 data line is connected to is specified in the measurement ins
20. 6 check the output of the sensor in the datalogger support software data display to make sure it is making reasonable measurements The heart of the OBS500 sensor is a near infrared NIR laser and two photodiodes for detecting the intensity of light scattered from suspended particles in water One detector measures the backscatter energy and the second is positioned at 90 degrees to the emitter to measure the sidescatter energy Backscatter and sidescatter sensors have unique strengths and weaknesses Generally speaking backscatter provides high range HR measurements and sidescatter provides low range LR measurements The OBS500 combines both in one sensor to provide unequalled performance in a field turbidity sensor With their unique optical design U S Patent No 4 841 157 backscatter sensors perform better than most in situ turbidity monitors in the following ways e Measure turbidity to 4000 TU compared to 1200 TU typically for sidescatter sensors e Insensitivity to bubbles and organic matter e Ambient light rejection e Low temperature coefficient User Manual Sidescatter sensors have the following advantages e More accurate in very clean water e Fixed measurement volume 5 1 Applications Turbidity sensors are used for a wide variety of monitoring tasks in riverine oceanic laboratory and industrial settings They can be integrated in water quality monitoring systems CTDs laboratory instrumentation and sedim
21. Do not exceed design limits Be familiar and comply with all instructions provided in product manuals Manuals are available at www campbellsci eu or by telephoning 44 0 1509 828 888 UK You are responsible for conformance with governing codes and regulations including safety regulations and the integrity and location of structures or land to which towers tripods and any attachments are attached Installation sites should be evaluated and approved by a qualified engineer If questions or concerns arise regarding installation use or maintenance of tripods towers attachments or electrical connections consult with a licensed and qualified engineer or electrician General e Prior to performing site or installation work obtain required approvals and permits Comply with all governing structure height regulations such as those of the FAA in the USA e Use only qualified personnel for installation use and maintenance of tripods and towers and any attachments to tripods and towers The use of licensed and qualified contractors is highly recommended e Read all applicable instructions carefully and understand procedures thoroughly before beginning work e Wear a hardhat and eye protection and take other appropriate safety precautions while working on or around tripods and towers e Do not climb tripods or towers at any time and prohibit climbing by other persons Take reasonable precautions to secure tripod and tower sites from trespassers
22. IVANVIA AAS CAMPBELL L7 SCIENTIFIC WHEN MEASUREMENTS MATTER OBS500 Smart Turbidity Meter with ClearSensor Technology 0 BS 5 0 Q rd ns un fa CAMPBELL Issued 8 6 15 Copyright 2008 2015 Campbell Scientific Inc Printed under licence by Campbell Scientific Ltd CSL 939 Guarantee This equipment is guaranteed against defects in materials and workmanship This guarantee applies for 24 months from date of delivery We will repair or replace products which prove to be defective during the guarantee period provided they are returned to us prepaid The guarantee will not apply to e Equipment which has been modified or altered in any way without the written permission of Campbell Scientific e Batteries e Any product which has been subjected to misuse neglect acts of God or damage in transit Campbell Scientific will return guaranteed equipment by surface carrier prepaid Campbell Scientific will not reimburse the claimant for costs incurred in removing and or reinstalling equipment This guarantee and the Company s obligation thereunder is in lieu of all other guarantees expressed or implied including those of suitability and fitness for a particular purpose Campbell Scientific is not liable for consequential damage Please inform us before returning equipment and obtain a Repair Reference Number whether the repair is under guarantee or not Please state the faults as clearly as possible and if the
23. SDI 12 address measurement mode and sidescatter ratio top Select the desired values and press the Apply button The SDI 12 address is not used while in analogue mode 7 3 Datalogger RTU Connection The OBS500 field cable is typically used to connect to a datalogger or RTU The field cable is a moulded cable assembly that terminates with an MCIL wet pluggable underwater terminator Table 7 3 shows the contact numbers for the MCIL MCBH 8 connectors and the electrical functions and wire colours 15 OBS500 Smart Turbidity Meter with ClearSensor Technology Table 7 3 OBS500 Connector Pin Out MCIL 8 MP MCBH 8 FS Contact Number Electrical Function Wire Colour Power Ground SDI 12 RS232 TX Analogue White SS BS Control Power 9 6 to 15 V Red RS 232 RX Shutter Open Analogue Ground This document provides the recommended wiring configuration for connecting the OBS500 field cable to a Campbell Scientific datalogger Wiring to dataloggers or RTUs manufactured by other companies is similar NOTE Campbell Scientific recommends powering down the system before wiring the OBS500 The shield wire plays an important role in noise emissions and susceptibility as well as transient protection 7 3 1 SDI 12 Wiring Table 7 4 SDI 12 Wiring CR6 CR800 CR5000 OBS500 CR3000 CR200X Function Series Signal gel ame oer Only odd control ports can be used for SDI 12 i e C1 C3 7 3 2 RS 232 Wiring Our CR800 CR85
24. Sci SC Win folder The file of interest has a DLD extension Select the file and click Open The dld file which is a type of ASCII machine code is imported documented and when saved given a CST extension Immediately save the file in a folder different from Campbellsci SCWin or save the file with a different file name Once the file is edited with Edlog Short Cut can no longer be used to edit the program Change the name of the program file or move 1t or Short Cut may overwrite it 5 6 The program can now be edited saved and sent to the datalogger Import wiring information to the program by opening the associated DEF file Copy and paste the section beginning with heading Wiring for CRXXX into the Edlog program usually at the head of the file After pasting edit the information such that a semicolon begins each line which instructs the datalogger compiler to ignore the line when compiling the datalogger code Appendix B Example Programs B 1 CR1000 SDI 12 Program Although this is a CR1000 program other CRBasic dataloggers are programmed similarly CR1000 Series Datalogger Declare Public Variables Public SDI 4 Declare Other Variables Alias SDI 1 OBS Alias SDI 2 SS Alias SDI 3 Temp Alias SDI 4 WetDry Define Data Tables DataTable Test 1 1000 DataInterval 0 15 Min 10 Sample 1 0BS FP2 Sample 1 SS FP2 Sample 1 Temp FP2 Sample 1 WetDry FP2 EndTa
25. after about 28 seconds send 0BS_500 gt and then the data CHR 62 is gt SerialIn InString Com1 100 13 209 Now the data comes ending with a carriage return CHR 13 SplitStr RS232 InString 5 0 Split the ASCII string into numeric variables Call Output Tables Example CallTable Test NextScan EndProg Appendix B Example Programs B 3 CR1000 Analogue Program Although this is a CR1000 program other CRBasic dataloggers are programmed similarly CR1000 Series Datalogger 0BS500_analog_0 amp M CR1 for the CR1000 wiring Green to 1H Brown to 1L Red to SW12 Black to Grnd Blue to C1 and White to C2 Declare Public Variables Public PTemp batt_volt Public Results 2 Alias Results 1 0bs Alias Results 2 ss Units obs NTU Units ss NTU DataTable 0BS500_analog 1 1 DataInterval 0 3 min 10 Minimum 1 batt_volt FP2 0 False Sample 1 PTemp FP2 Sample 1 obs FP2 Sample 1 ss FP2 EndTable Main Program BeginProg Scan 30 sec 3 0 PanelTemp PTemp 250 Battery batt_volt PortSet 1 1 blue wire drive high to open shutter PortSet 2 0 white wire selects obs 8 or ss 1 Delay 0 9500 msec 6 secs shutter open 3 5 secs VoltDiff obs 1 0 1 1 0 60Hz 1 0 1 mV 1 TU PortSet 2 1 white wire to 5 volts for ss meas Delay 0 800 msec wait until meas is done VoltDiff ss 1 0 1 1 0 _60Hz 1 0 PortSet 1 0 blue wire drive low to close shutter CallTable 0BS500_analog
26. ations command to enter SDI 12 transparent mode is nX lt Enter gt where n is the control port being used for SDI 12 For example if the selected control port is C1 the command would be 1X lt Enter gt In response the datalogger opens the link to control port 1 and responds with a prompt CR10X and CR510 dataloggers reply with entering SDI 12 CR10X PB and CR510 PB dataloggers require n being entered at the prompt where n is the control port being used Now check for a response from the sensor with address zero by typing the SDI 12 identify command OI lt Enter gt that s a zero not the letter O The sensor should respond with an identification string similar to 013CSI Std 01_xxxxxxxx where XXXXXXXX represents the eight digit serial number Note that the SDI 12 standard allows for multiple probes to be connected to one datalogger control port For example if you have another SDI 12 probe on C1 that has address 7 you could issue the identify command 71 lt Enter gt Only one sensor of the same address can be connected when using the change address command 21 OBS500 Smart Turbidity Meter with ClearSensor Technology 22 7 4 2 RS 232 RS 232 measurements of the OBS500 are typically made by a CR800 CR850 CR1000 or CR3000 datalogger or an RTU device The OBS500 field cable is used and wired appropriately for the measurement device See Table 7 8 for settings Table 7 8 RS 232 Settings Measurement comma
27. bellsci co uk Campbell Scientific Ltd France 3 Avenue de la Division Leclerc 92160 ANTONY FRANCE www campbellsci fr e info campbellsci fr Campbell Scientific Spain S L Avda Pompeu Fabra 7 9 Local 1 08024 BARCELONA SPAIN www campbellsci es e info campbellsci es Campbell Scientific Ltd Germany Fahrenheitstrasse13 D 28359 Bremen GERMANY www campbellsci de info campbellsci de Campbell Scientific Beijing Co Ltd 8B16 Floor 8 Tower B Hanwei Plaza 7 Guanghua Road Chaoyang Beijing 100004 P R CHINA www campbellsci com e info campbellsci com cn Please visit www campbellsci com to obtain contact information for your local US or International representative
28. ble Main Program BeginProg Scan 30 Sec 0 0 SDI12Recorder SDI 1 0 M 1 0 0 Call Output Tables CallTable Test NextScan EndProg B 1 Appendix B Example Programs B 2 CR1000 RS 232 Program Although this is a CR1000 program other CRBasic dataloggers are programmed similarly CR1000 Series Datalogger Declare Public Variables Public RS232 5 Public Counter Public OutString As String 20 Public OutString2 As String 10 Public InString As String 100 Declare Other Variables RS232 1 is the address Alias RS232 2 OBS Alias RS232 3 SS Alias RS232 4 Temp Alias RS232 5 WetDry Define Data Tables DataTable Test 1 1000 DataInterval 0 60 Min 10 Sample 1 0BS FP2 Sample 1 SS FP2 Sample 1 Temp FP2 Sample 1 WetDry FP2 EndTable Main Program BeginProg SerialOpen Com1 9600 0 0 150 Scan 30 Sec 0 0 OutString2 CHR 13 a series of carriage returns will put 0BS500 into RS 232 mode OutString M CHR 13 address and then use commands M to M8 Send String over communication port C1 COM1 TX SerialOut Com1 OutString2 OBS _500 15 10 put OBS5 into RS232 mode delay 1 1 Sec SerialOut Com1 OutString 0 1000 send command Receive String over communication port C1 COM1 RX SerialIn InString Com1 5 33 150 The sensor echoes back the command ending with an CHR 33 SerialIn InString Com1 2500 62 150 The sensor will open close and
29. downstream e The probe must be calibrated with sediments from the waters to be monitored The procedure for calibrating the probe is provided in Section 7 5 Calibration OBS500 Smart Turbidity Meter with ClearSensor Technology Sites with high sediment loads or large sand grains can be problematic for the shutter and it s motor Refer to Section 7 7 Operation in High Sediment Loads and Sandy Sediments for more information The OBS500 will be damaged if it is encased in frozen liquid Use electrical tape or neoprene to pad the parts of the OBS500 housing that will contact metal or other hard surfaces Remember that although the OBS500 is designed to be a rugged and reliable device for field use it is also a highly precise scientific instrument and should be handled as such 3 Initial Inspection 3 1 Ships With Upon receipt of the OBS500 inspect the packaging for any signs of shipping damage and if found report the damage to the carrier in accordance with policy The contents of the package should also be inspected and a claim filed if any shipping related damage is discovered When opening the package care should be taken not to damage or cut the cable jacket If there is any question about damage having been caused to the cable jacket a thorough inspection is prudent The model number is engraved on the housing Check this information against the shipping documentation to ensure that the expected model number wa
30. e Sonic Bath Turbidity NTU 20 Hand Shaking Least Aggressive 10 20 30 40 50 Concentration mg r1 Figure 8 2 The apparent change in turbidity resulting from disaggregation methods 8 2 Suspensions with Mud and Sand As mentioned in Section 8 1 Particle Size light scattering from particles is inversely related to particle size on a mass concentration basis This can lead to serious difficulties in flow regimes where particle size varies with time For 33 OBS500 Smart Turbidity Meter with ClearSensor Technology 34 example when sandy mud goes through a cycle of suspension and deposition during a storm the ratio of sand to mud in suspension will change A turbidity sensor calibrated for a fixed ratio of sand to mud will therefore indicate the correct concentration only part of the time There are no simple remedies for this problem One solution is to take a lot of water samples and analyse them in the laboratory This is not always practical during storms when the errors are likely to be largest Do not rely solely on turbidity sensors to monitor suspended sediments when particle size or composition is expected to change with time at a monitoring site 8 3 Particle Shape Effects In addition to size and flocculation aggregation particle shape has a significant effect on the scattering intensity from a sample and calibration slope of a turbidity sensor As the graph in Figure 8 3 shows plate shaped particl
31. e clay mineral particles for example backscatter light about ten times more efficiently than spherical particles and angular shapes have intermediate scattering efficiency Turbidity sensors are very sensitive to shape effects and this makes it very important to calibrate with material from the monitoring site It is also essential that particle shape remains constant during the monitoring period OBS 3 1 Plates Cubes e a Spheres Relative Scattering Intensity 0 01 0 20 40 60 80 100 120 140 160 180 Scattering Angle Figure 8 3 Relative scattering intensities of grain shapes 8 4 High Sediment Concentrations At high sediment concentrations particularly in suspensions of clay and silt the infrared radiation from the emitter can be so strongly attenuated along the path connecting the emitter the particle and the detector that backscatter decreases exponentially with increasing sediment concentration For mud this occurs at concentrations greater than about 5 000 mg l Figure 8 4 shows a calibration in which sediment concentrations exceeding 6 000 mg l cause the output signal to decrease It is recommended not to exceed the specified turbidity or suspended sediment ranges otherwise the interpretation of the signal can be ambiguous For example a signal level of 2 000 mV Figure 8 4 could be interpreted to indicate User Manual SSC values of either 3 000 or 33 000 mg l Factory calibrations are performed in the
32. e 33 Relative scattering intensities of grain shape iese se see ses ee ee 34 Response of an OBS sensor to a wide range of SSC 35 Infrared reflectivity of minerals as a function of 10 Munzell Valle aan ide 36 EET Ao RE ana 38 Factory Settings EE EE EE EE AR EE 13 RS 232 Terminal Commands esse ee ee ee Se Se Re Ge Re 14 OBS500 Connector Pin Out ii 16 SDI 12 Wiring RS 232 Wiring Analogue 0 5 Volt Wiring noc nccnnccnnonnss 17 SDI 12 and RS 232 Measurement Commands for OS Version 2 ed sil ener ee eee Ra 18 RS 232 EE EE laser anna 22 Calibration Materials and Volumes ee Re ee GR Re ee 23 Change in TU value resulting from one hour of evaporation of SDVB standard i e loss of water but not particles 24 Troubleshooting Chart corona noc ee Re ee 39 SDI 12 and RS 232 Measurement Commands se se D 1 OBS500 Smart Turbidity Meter with ClearSensor Technology 1 Introduction The OBS500 submersible turbidity meter is designed for general pressure measurements The OBS500 uses ClearSensor U S Patent No 8 429 952 an anti fouling scheme that uses a shutter wiper mechanism to protect and clean the optics and a refillable biocide chamber to allow biocide to leach out over the optics continually while in the closed position It uses the SDI 12 or RS 232 communication protocol to communicate with a
33. e OBS500 sensor i 10 5 2 Orientation of emitter cone source beam and OBS and sidescatter detector acceptance CONES ii 11 7 1 Device Configuration Utility iii 13 7 2 Terminal Mode using 1 and H commands esse se ee ee ee ee ge ee 14 137 Settings Editor SCreen ses gese ee eg tati 15 7 4 Terminal Emulator 82222 ia 21 7 5 Normalized response of OBS500 to AMCO Clear turbidity The inset shows the response function of a turbidity sensor to high sediment concentrations iii 23 Tables 7 6 7 7 7 8 7 10 7 11 7 12 8 1 8 2 8 3 8 5 9 1 7 1 7 2 7 3 7 4 7 6 7 7 7 8 7 9 7 10 10 1 D 1 Position of OBS500 in clean tap water in big black tub 25 OBS500 in 500 TU AMCO Clear turbidity standard in 100 mm black polyethylene calibration CUP see see se ee ee ee Se ee ke 26 Portable Sediment Suspender left and OBS beam orientation in suspender tub right iii 27 Remove AA ni ieri lenti 31 Insert screwdriver and rotate clockwise i 31 Shutter disassembled iii 31 Shutter COMPONEN S ii 32 Normalized sensitivity as a function of grain diameter 33 The apparent change in turbidity resulting from disaggregation Methods SE EED A ER Ge RE ED Ge GE GR RE Ge Ee E
34. ent transport monitors The electronics of the OBS500 are housed in a Delrin package which is ideal for salt water or other harsh environments Applications include e Compliance with permits water quality guidelines and regulations Determination of transport and fate of particles and associated contaminants in aquatic systems Conservation protection and restoration of surface waters Assess the effect of land use management on water quality Monitor waterside construction mining and dredging operations Characterization of wastewater and energy production effluents Tracking water well completion including development and use 5 2 Turbidity Units Conceptually turbidity is a numerical expression in turbidity units TU of the optical properties that cause water to appear hazy or cloudy as a result of light scattering and absorption by suspended matter Operationally a TU value is interpolated from neighbouring light scattering measurements made on calibration standards such as Formazin StablCal or SDVB beads Turbidity is caused by suspended and dissolved matter such as sediment plankton bacteria viruses and organic and inorganic dyes In general as the concentration of suspended matter in water increases so will its turbidity as the concentration of dissolved light absorbing matter increases turbidity will decrease Descriptions of the factors that affect turbidity are given in Section 8 Factors that Affect Turbidity and Su
35. ent as follows Wi 2500 mg 4000 Vx where Wi the incremental weigh of sediment and Vx the average output signal from step 6 The resulting weight gives the amount of sediment to add in order to have evenly spaced calibration points Add enough additional sediment to get one full increment of sediment Wi 5 Repeat steps 4 5 and 6 Repeat step 8 until five full increments of sediment have been added or until the OBS signals exceed the output range Perform 3 order polynomial regressions on the data to get the coefficients for converting OBS output to SSC 7 6 Programming 7 6 1 Using SCWIN SCWIN is the easiest and typically the preferred method for programming the datalogger SCWIN generates a wiring diagram that shows how to connect the OBS500 to your Campbell Scientific datalogger NOTE The sections that immediately follow are for CRBasic and Edlog SCWIN users can jump ahead to Section 9 Maintenance 7 6 2 CRBasic Programming Dataloggers that use CRBasic include our CR200X series CR800 CR850 CR1000 CR3000 and CR5000 dataloggers 7 6 2 1 SDI 12 Programming The SDI12Recorder instruction is used to read the OBS500 in SDI 12 mode A multiplier of 1 0 and an offset of 0 0 yield water level in psig and temperature in degrees C User Manual The SDI12Recorder instruction has the following form SDI12Recorder Destination Output String Multiplier Offset Refer to Appendix B 1 CR1000 SDI 12 Program
36. ested The recommended frequency for calibration checks is quarterly when an OBS sensor is in regular use Otherwise it should be performed prior to use Calibration checks can be done in the field Table 10 1 Troubleshooting Chart Fails finger No power dead battery Replace battery and reconnect wave test wires Plug not fully seated Disconnect and reinsert plug Sensor broken Visually inspect for cracks Return OBS500 to manufacturer if cracks are found Electronic failure Unit Return OBS500 to manufacturer draws less than 11 mA or more than 40 mA Fails shake Sensor leaked Return OBS500 to manufacturer test Fails Aging of light source Recalibrate see Section 7 5 calibration causes it to become dimmer Calibration check with time 39 OBS500 Smart Turbidity Meter with ClearSensor Technology 11 References 40 Anderson C W 2005 Turbidity ver 2 1 U S Geological Survey Techniques of Water Resources Investigations book 9 chap A6 sec 6 7 Sept 2005 accessed December 8 2011 from http pubs water usgs gov twri9A6 Boyd Bringhurst and Jeff Adams Innovative Sensor Design for Prevention of Bio fouling Oceans 2011 September 2011 Lewis Jack 1996 Turbidity controlled Suspended Sediment Sampling for Runoff event Load Estimation Water Resources Research 32 7 pp 2299 2310 U S Geological Survey Implements New Turbidity Data Reporting Procedures U S Geological Survey h
37. file wil configure the datalogger such that t wa 1 retreve backscatter turbidity sidescatter turbiSity NE temperature measurement and condition Omdry Immer of 500 the mater trom the OES Backscatter Turbi ty units are FBU Formanin Backscatter OBS500 Smart Turbidity Meter with ClearSensor Technology 5 Overview 6 After selecting the sensor click at the left of the screen on Wiring Diagram to see how the sensor is to be wired to the datalogger The wiring diagram can be printed out now or after more sensors are added Short Cut CR1000 Eile Program Tools Help CR1000 Progress 1 New Open CR1000 Wiring Diagram for untitied scw Wiring details can be found in the help file 2 Datalogger 085500 Turb Turb Temp WD_OBS 3 Sensors an FARAI I Red 4 Outputs 5 Finish white Black Clear Wiring Wiring Diagram lt Wiring Text 7 Select any other sensors you have and then finish the remaining Short Cut steps to complete the program The remaining steps are outlined in Short Cut Help which is accessed by clicking on Help Contents Programming Steps 8 If LoggerNet PC400 or PC200W is running on your PC and the PC to datalogger connection is active you can click Finish in Short Cut and you will be prompted to send the program just created to the datalogger 9 Ifthe sensor is connected to the datalogger as shown in the wiring diagram in step
38. gov owq turbidity TurbidityInfoSheet pdf Throughout this manual the measurements will simply be referred to as Turbidity Units TU Figure 5 1 Drawing of the OBS500 sensor 5 3 Measurement Details The OBS500 design combines the sensor analogue measurement and signal processing within a single housing resulting in the integration of state of the art sensor and measurement technology The 24 bit A D has simultaneous 50 60 Hz rejection and automatic calibration for each measurement A number of additional advanced measurement techniques are employed to harness the best possible performance available from today s state of the art sensor technology The sensor reverts to a low power sleep state between measurements A series of measurements is performed yielding two turbidity and one temperature value This measurement cycle takes about 20 seconds The measurement cycle is activated by commands via SDI 12 RS 232 terminal commands or a control line s going high analogue measurements The OBS500 has three communication modes SDI 12 RS 232 or 0 to 5 V The mode defaults to SDI 12 RS 232 but can be set in our Device Configuration Utility DevConfig to analogue As an SDI 12 RS 232 sensor the OBS500 is shipped with an address of 0 With SDI 12 and RS 232 the basic values output by the OBS500 are backscatter turbidity sidescatter turbidity and temperature The OBS500 can also output a ratiometric measurement that combines the back
39. h ClearSensor Technology 20 7 4 1 1 SDI 12 Addresses The OBS500 SDI 12 address can be set to 0 to 9 A to Z or a to z which allows multiple sensors to be connected to a single digital I O channel control port of an SDI 12 datalogger Most Campbell Scientific dataloggers support SDI 12 The OBS500 is shipped from the factory with the address set to 0 When it is necessary to measure more than one OBS500 it is easiest to use a different control port for each OBS500 instead of changing the address If additional control ports are not available the address will need to be changed The address on the OBS500 can be changed by sending the SDI 12 change address command aAb The change address command can be issued from most SDI 12 recorders For example to change the address of a sensor that has a default address of O to the address of 1 the following command can be sent 0A1 The address may also be changed by connecting to the probe in DevConfig Once connected in the Settings Editor tab click in the address box and enter the new address Press Apply to save the changes 7 4 1 2 SDI 12 Transparent Mode The transparent mode allows direct communication with the OBS500 This may require waiting for programmed datalogger commands to finish before sending responses While in the transparent mode datalogger programs may not execute Datalogger security may need to be unlocked before the transparent mode can be activated The trans
40. linear region designated A on the graph 4000 ni A B 2000 Signal mV 1000 0 20000 40000 60000 SSC mg l Figure 8 4 Response of an OBS sensor to a wide range of SSC 8 5 IR Reflectivity Sediment Colour Infrared reflectivity indicated by sediment colour has a major effect on sensitivity because with other factors remaining constant it changes the intensity of light scattering Although turbidity sensors are colour blind tests have shown that whiteness colour and IR reflectivity are correlated Calcite which is highly reflective and white in colour will produce a much stronger turbidity signal on a mass concentration basis than magnetite which is black and IR absorbing Sensitivity to coloured silt particles varies from a low of about one for dark sediment to a high of about ten for light grey sediment see Figure 8 5 In areas where sediment colour is changing with time a single calibration curve may not work Resulting errors will depend on the relative concentrations of coloured sediments 35 OBS500 Smart Turbidity Meter with ClearSensor Technology 36 1 0 Calcite 0 8 Andesine o Montmorillonite Labradorite 865 nm Reflectivity e Actinolite e gt 0 2 Hornblende Magnetite 0 0 4 6 8 Munzell Value 0 Black 10 White Figure 8 5 Infrared reflectivity of minerals as a function of 10 Munzell Value 8 6 Water Colour Some OBS users have been concer
41. m the ResourceDVD or find it in installations of LoggerNet PC200W PC400 or RTDAQ software E SOW IN The Short Cut installation should place a Short Cut icon on the desktop of your computer To open Short Cut click on this icon Di When Short Cut opens select New Program File Program Tools Help Test Progress 1 New Open Welcome to Short Cut Short Cut will help you generate a datalogger program The basic steps are 1 Create New Open Program 2 Select Datalogger 3 Select Sensors 4 Select Outputs 5 Finish Compile the Program lt Click New Program to begin Click Open Program to open an existing Short Cut program Open Program User Manual 4 Select Datalogger Model and Scan Interval default of 5 seconds is OK for most applications Click Next Eile Program Tools Progress 1 New Open 2 Datalogger 3 Sensors 4 Outputs 5 Finish Wiring Wiring Diagram Wiring Text Help Test Datalogger Model Select the Datalogger Model for E which you wish to create a program Scan Interval Select the Scan Interval nai This is how frequently Seconds nr lt a measurements are made 5 Under the Available Sensors and Devices list select the Sensors Water Quality folder Select OBS500 Smart Turbidity Meter Click E to move the selection to the Selected device window Temperature defaults to degrees Celsius and the sensor are
42. n SDI 12 or RS 232 recorder simplifying installation and programming It can also be used as an analogue sensor with 0 to 5 V output Before using the OBS500 please study e Section 2 Cautionary Statements e Section 3 Initial Inspection e Section 4 Quickstart 2 Cautionary Statements e READ AND UNDERSTAND the Precautions section at the front of this manual e The OBS500 needs to be sent in after two years or 70 000 cycles for drive shaft seal replacement See m8 command in Table 7 7 e The sensor may be damaged if it is encased in ice e Damages caused by freezing conditions will not be covered by our warranty e Campbell Scientific recommends removing the sensor from the water for the time period that the water is likely to freeze e Sand grains between moving surfaces can jam the shutter wiper For high sediment load and large grain size installations operate the OBS500 normally open to minimize the chance of sand grains jamming the shutter wiper and orient the sensor vertically facing downstream see Section 7 7 Operation in High Sediment Loads and Sandy Sediments e Minimize temperature shock For example do not take sensor from sunny dashboard and immediately drop it in frigid water e Ensure that obstructions are not in the backscatter sensor s large field of view See Section 4 Quickstart for more information e Maximum depth for the OBS500 is 100 metres e If possible orient the unit vertically and facing
43. ncurrent recorded OBS500 signals and regression analysis establishes the mathematical relation for future SSC conversions by an instrument This is the best sediment calibration method because the particles are not altered from their natural form in the river see Lewis 1996 It is also the most tedious expensive and time consuming method It can take several years of water sampling with concurrent OBS measurements to record the full range of SSC values on a large river 7 5 2 4 Performing a Dry Sediment Calibration Materials and equipment OBS500 with test cable dry disaggregated sediment from the location where the OBS500 will be used sediment should be in a state where grinding sieving or pulverization does not change its particle size distribution datalogger with 12 V power supply sediment suspender if a suspender is not available use a 200 mm I D dark plastic container and a drill motor with paint mixing propeller electronic balance calibrated with 10 mg accuracy 20 ml weigh boats large black polyethylene plastic tub for measuring the clear water points 1 litre class A volumetric flask tea cup with round bottom and teaspoon 1 Check the balance with calibration weights recalibrate if necessary 2 Connect the OBS500 to a computer or datalogger so that the measured values can be observed Add three litres of tap water to the suspender tub with the volumetric flash 4 After measuring the clear water signal Step
44. nds are the same for RS 232 and SDI 12 as shown in Table 7 7 7 5 Calibration 7 5 1 Turbidity Field recalibration is not recommended and usually not needed until the OBS500 is sent back to Campbell Scientific for the two year service We recommend checking the calibration in the field as described below Ifa 9 point calibration is needed the OBS500 should be sent to Campbell Scientific to perform the calibration The normalized response of an OBS500 sensor to SDVB turbidity over the range from 0 to 4 000 TU is shown in Figure 7 5 As shown on the inset the response function is contained within region A the linear region of the universal response curve However there is residual nonlinearity that is removed by calibration and by computation of a TU value with a 2nd order polynomial This section explains how to do a turbidity calibration User Manual 0 8 0 6 0 4 Normalized OBS 3 Response OPV330 VCSEL 0 2 Turbidity NTU 0 0 0 1000 2000 3000 4000 Tur bidity TU Figure 7 5 Normalized response of OBS500 to AMCO Clear turbidity The inset shows the response function of a turbidity sensor to high sediment concentrations AMCO Clear SDVB turbidity standards are used to calibrate an OBS500 sensor SDVB standards are made for individual instruments Standards made for one model of turbidity meter cannot be used to calibrate a different model
45. ned that colour from dissolved substances in water samples not coloured particles as discussed in Section 8 5 IR Reflectivity Sediment Colour produces erroneously low turbidity measurements Although organic and inorganic IR absorbing dissolved matter has visible colour its effect on turbidity measurements is small unless the coloured compounds are strongly absorbing at the sensor wavelength 850 nm and are present in high concentrations Only effluents from mine tailings produce enough colour to absorb measurable IR In river estuary and ocean environments concentrations of coloured materials are too low by at least a factor of ten to produce significant errors 8 7 Bubbles and Plankton Although bubbles efficiently scatter light monitoring in most natural environments shows that OBS signals are not strongly affected by bubbles The sidescatter measurement may be more affected Bubbles and quartz particles backscatter nearly the same amount of light to within a factor of approximately four but most of the time bubble concentrations are at least two orders of magnitude less than sand concentrations This means that sand will produce much more backscatter than bubbles in most situations and bubble interference will not be significant Prop wash from ships and small clear mountain streams where aeration produces high bubble concentrations are exceptions to this generality and can produce erroneous turbidity values resulting from bubbles
46. ollow the directions provided in Section 7 7 1 Wiper Removal Procedure Flush and clean Store the current used to open and close the slider The open and close SDI 12 instructions M3 and M7 output the current Normally the current is around 100 mA As sand grits lodge in the groves the resistance to movement increases and the motor has to work harder This increases the current usage Therefore increased current usage indicates that the wiper needs to be cleaned see step 2 Mount the sensor between 45 degrees pointing down to vertical hanging down 7 7 1 Wiper Removal Procedure 1 Remove the stop screw in the OBS500 housing at the end of the shutter wiper slot 2 Remove the 4 40 flat head screw and copper plate to expose the drive shaft access port Figure 7 9 3 Insert a slot screw driver 2 5 mm 0 1 in wide blade into the access port Figure 7 10 4 Engage the end of the drive shaft and then rotate clockwise until the shutter is free Figure 7 10 and Figure 7 11 CAUTION Keep track of all of the components Figure 7 12 5 Reassemble by reversing the steps User Manual Remove 4 40 flat head screw Drive shaft access port Figure 7 11 Shutter disassembled 31 OBS500 Smart Turbidity Meter with ClearSensor Technology 8 32 Floating nut spacer e O EE Bere 4 Figure 7 12 Shutter components Factors that Affect Turbidity and Suspended Sediment Measurements This section s
47. on of OBS500 in clean tap water in big black tub 2 Pour the first SDVB standard into the appropriately sized cup see Table 7 9 3 Position the OBS sensor in the cup as shown in Figure 7 7 and record 10 second averages of the low and high range outputs Record the average outputs on the calibration log sheet 4 Pour the standard back into its container 5 Wipe sensor with a clean dry towel to remove residual standard 6 Repeat steps 2 3 4 and 5 for the other standards 7 Perform 2 order polynomial regressions on the calibration data to get the coefficients for converting OBS signals to TU values 25 OBS500 Smart Turbidity Meter with ClearSensor Technology 26 7 5 2 Sediment Figure 7 7 OBS500 in 500 TU AMCO Clear turbidity standard in 100 mm black polyethylene calibration cup There are three basic ways to calibrate an OBS sensor with sediment These are described in the following sections However only the procedures for dry sediment are explained in this manual Typically the sensor will record in turbidity units and the relationship to suspended sediment is calculated in a spread sheet or database after the data is retrieved to a computer 7 5 2 1 Dry Sediment Calibration Dry sediment calibration is a calibration performed with sediment that has been dried crushed and turned to powder This is the easiest calibration to do because the amount of sediment can be determined accurately with an electr
48. onic balance and the volume of water in which it is suspended can be accurately measured with volumetric glassware Of the three methods dry sediment calibration causes the greatest physical and chemical alteration of the sediment Alteration of the sediment size as a result of processing can significantly affect the calibration slope Figure 7 5 shows for example that reducing the grain size by a factor of two during grinding can increase OBS sensitivity by a factor of two 7 5 2 2 Wet Sediment Calibration Wet sediment calibration is performed with sediment obtained from water samples or from the bed of a river that has not been dried and pulverized Consolidation and biochemical changes during storage and processing cause some alteration of wet sediment and for this reason sediment and water samples should be stored at about 4 C prior to use The wet sediment is introduced into the sediment suspender as it comes from the field This kind of calibration requires that water samples be withdrawn from the suspender after each addition of sediment for the determination of SSC suspended sediment concentration by filtration and gravimetric analysis User Manual 7 5 2 3 In situ Calibration In situ calibration is performed with water samples taken from the immediate vicinity of an OBS sensor in the field over sufficient time to sample the full range of SSC values to which a sensor will be exposed SSC values obtained for these samples with co
49. ovide structure and protection for deployments The OBS500 will fit inside a 2 in schedule 40 PVC pipe The most convenient means for mounting the unit to a frame or wire is to use large high strength nylon cable ties 7 6 mm 0 3 in width or stainless steel hose clamps First cover the area s to be clamped with tape or 2 mm 1 16 in neoprene sheet Clamp the unit to the mounting frame or wire using the padded area Do not tighten the hose clamps more than is necessary to produce a firm grip Overtightening may crack the pressure housing and cause a leak Use spacer blocks when necessary to prevent chafing the unit with the frame or wire Mounting Example Figure 4 1 Use strain relief to keep stress off the cable and provide extra security OBS500 Smart Turbidity Meter with ClearSensor Technology Figure 4 2 Apply tape to protect sensor Dual Path Smart Turbidity Meter n USA a pr 109000 se Figure 4 3 Secure with hose clamps Do not overtighten User Manual Figure 4 4 Place and secure mounting fixture OBS500 Smart Turbidity Meter with ClearSensor Technology 4 2 Datalogger Programming and Wiring Short Cut is an easy way to program your datalogger to measure the sensor and assign datalogger wiring terminals The following procedure shows using Short Cut to program the OBS500 1 Install Short Cut by clicking on the install file icon Get the install file from either www campbellsci co
50. parent mode is entered while the PC is in telecommunications with the datalogger through a terminal emulator program It is most easily accessed through Campbell Scientific datalogger support software but it is also accessible with terminal emulator programs such as Windows Hyperterminal To enter the SDI 12 transparent mode enter the terminal emulator from LoggerNet PC400 or PC200W datalogger support software A terminal emulator screen is displayed Click the Open Terminal button For CR800 series CR1000 and CR3000 dataloggers press lt Enter gt until the datalogger responds with the prompt e g CR1000 gt for the CR1000 Type SDII2 at the prompt and press lt Enter gt In response the query Enter Cx Port 1 3 5 or 7 will appear Enter an integer value indicating the control port to which the OBS500 is connected A response of Entering SDI12 Terminal indicates that SDI 12 Transparent Mode is active Any of the SDI 12 commands may be entered e g aM1 where a refers to the address After entering a command the results may be viewed by entering aD Terminal Emul EE N Active CR800 gt SDI12 Enter Cx Port 1 or 3 1 Entering SDI12 Terminal OM 00204 Select Device Baud Rate User Manual CR8DOSeries All Caps Mode E Pause 115200 Close Terminal Clear Help Figure 7 4 Terminal Emulator For CR10X and CR510 standard mixed array dataloggers the datalogger telecommunic
51. per TU For example 100 mV 100 TU 4000 mV 4000 TU 7 4 Communication Modes 7 4 1 SDI 12 The OBS500 uses an SDI 12 compatible hardware interface and supports a subset of the SDI 12 commands The most commonly used command is the aM command issued by the datalogger Here a represents the sensor address 0 to 9 The communication sequence begins with the datalogger waking the sensor and issuing the aM command The sensor responds to the datalogger indicating that 17 OBS500 Smart Turbidity Meter with ClearSensor Technology 18 NOTE two measurements will be ready within two 2 seconds Subsequent communications handle data reporting from the sensor to the datalogger The SDI 12 protocol has the ability to support various measurement commands Table 7 7 provides the commands available for the OBS500 operating system OS version 2 or higher If you have OS version 1 see Appendix D SDI 12 and RS 232 Measurement Commands for OS Version 1 Use the al SDI 12 command or use DevConfig to see the OS version downloaded to your OBS500 The OS version can be updated by using DevConfig Table 7 7 SDI 12 and RS 232 Measurement Commands for OS Version 2 or Higher aM aC a address Open Wiper Measure Close Send Data Open Wiper Measure Close Send Data Open Wiper Measure Close Send Data Open Wiper Send Data Measure Send Data obs tu ss tu temperature C wet dry 0 dry 1 wet burs
52. r enter RS 232 commands and update the operating system Use the OBS500 test cable to connect the OBS500 to a computer running DevConfig The red wire is connected to a 12 Vdc power supply and the black to ground The datalogger power supply is a good choice to use for the power supply DevConfig software is shipped on the Campbell Scientific ResourceDVD included with the OBS500 NOTE The OBS500 is supported in DevConfig version 1 16 or higher r Device Configuration Utility 2 00 o BE X File Options Help Device Type 085500 send OS AVW200 Series a og OBS500 D295 COM220 In order to connect to the OBS500 you must connect the probe s RX TX and ground leads to a serial port on your COM320 5 3 CR1000 computer This is most easily done by using the OBS500 test cable CR10X CR10X PB CR10X TD CR200 Series CR23X CR23X PB CR23X TD CR3000 CR5000 CR510 CR510 PB CR510 TD R800 Series CR9000X S120 CS450 CS650 Series CWB100 CWS220 CWS655 CWS900 EC100 m CEET PS200 CH200 RF400 RF401 RF430 RF450 PC Serial Port COM1 n Baud Rate 9600 Z Figure 7 1 Device Configuration Utility After installing DevConfig select the OBS500 in the Device Type selection Select the correct PC Serial Port and then click Connect see Figure 7 1 13 OBS500 Smart Turbidity Meter with ClearSensor Technology 14 The Terminal tab can be used to verify the
53. r position count open max current count open timeout count open current ma obs tu ss tu temperature degc wet dry 0 dry 1 wet ratio tu temperature degc wet dry 0 dry 1 wet obs tu ss tu ratio tu temperature degc raw obs volts raw ss volts open current ma close current ma wet dry 0 dry 1 wet D 1 Appendix D SDI 12 and RS 232 Measurement Commands for OS Version 1 NOTE Table D 1 SDI 12 and RS 232 Measurement Commands Commands Process aM7 Close Wiper aC7 Send Data aM8 Send Wiper Data aC8 aC9 Open Wiper Measure 100 Times Close Send Data Values Returned Close wiper position count Close max current count Close timeout count Close current ma Open close total count Open wiper position count Open max current count Open timeout count Close wiper position count Close max current count Close timeout count obs median obs mean obs standard deviation obs min obs max ss median ss mean ss standard deviation ss min ss max With the SDI 12 concurrent measurements aCx the datalogger does not request the data until the next interval hits For example if you have a 30 minute interval you will not see the data for 30 minutes There is not an equivalent M command to the aC9 command since the M command is limited to nine returned values As the measurement data is transferred between the probe and datalogger digitally there are no offset er
54. rors incurred with increasing cable length as seen with analogue sensors However with increasing cable length there is still a point when the digital communications will break down resulting in either no response or excessive SDI 12 retries and incorrect data due to noise problems Using SDI 12 commands which add a CRC check e g aMC can significantly improve incorrect data issues CAMPBELL SCIENTIFIC COMPANIES Campbell Scientific Inc CSI 815 West 1800 North Logan Utah 84321 UNITED STATES www campbellsci com e info campbellsci com Campbell Scientific Africa Pty Ltd CSAf PO Box 2450 Somerset West 7129 SOUTH AFRICA www csafrica co za e salesOcsafrica co za Campbell Scientific Australia Pty Ltd CSA PO Box 8108 Garbutt Post Shop QLD 4814 AUSTRALIA www campbellsci com au e info campbellsci com au Campbell Scientific do Brazil Ltda CSB Rua Apinag s nbr 2018 Perdizes CEP 01258 00 S o Paulo SP BRAZIL www campbellsci com br e vendas 2campbellsci com br Campbell Scientific Canada Corp CSC 14532 131 Avenue NW Edmonton Alberta T5L 4X4 CANADA www campbellsci ca e dataloggers campbellsci ca Campbell Scientific Centro Caribe S A CSCC 300N Cementerio Edificio Breller Santo Domingo Heredia 40305 COSTA RICA www campbellsci cc e info campbellsci cc Campbell Scientific Ltd CSL 80 Hathern Road Shepshed Loughborough LE12 9GX UNITED KINGDOM www campbellsci co uk e sales camp
55. s 4 Transfer entire bottles between containers To avoid aeration do not shake excess fluid off the glassware Because of the intrinsic errors in the TU value of formazin used by the SDVB manufacturer GFS Chemicals and the dilution procedures the uncertainty in the TU value of an SDVB standard is 1 of the value indicated on the standard bottle Consequently the TU value of one litre of standard in an uncovered 100 mm calibration cup will increase 1 in 10 hours on a typical summer day R H 90 and air temp 18 C For example the TU value of a 2000 TU standard in a 100 mm cup will increase by about 2 TU 0 1 per hour Table 7 10 gives the increases for some other commonly used standards Table 7 10 Change in TU value resulting from one hour of evaporation of SDVB standard i e loss of water but not particles Calibration cup Size q mm 6 in 250 TU 500 TU 2000 TU 4000 TU cao Sieg Materials and equipment OBS500 with cable datalogger large black polyethylene plastic tub 0 5 M I D X 0 25 M deep for measuring the clear water points and 100 mm and 200 mm black PE polyethylene calibration cups Procedure 1 Swab sensor with an alcohol soaked towel to sterilize it Position the OBS sensor in a large black tub of fresh tap water as shown in Figure 7 6 and record a 10 second average of the low range output Record the average output on the calibration log sheet User Manual Figure 7 6 Positi
56. s received Refer to the Ships With list to ensure that all parts are included see Section 3 1 Ships With 1 Calibration Certificate 1 27752 OBS500 Spare Parts Kit 1 ResourceDVD 4 Quickstart 4 1 Mounting Suggestions Maximum depth for the OBS500 housing is 100 metres Schemes for mounting the OBS500 will vary with applications however the same basic precautions should be followed to ensure the unit is able to make a good measurement and that it is not lost or damaged CAUTION User Manual e The most important general precaution is to orient the unit so that the OBS sensor looks into clear water without reflective surfaces This includes any object such as a mounting structure a streambed or sidewalls The backscatter sensor in the OBS500 can see to a distance of about 50 cm 20 in in very clean water at angles ranging from 125 to 170 The sidescatter SS sensor can only see to about 5 cm 2 in at 90 e The sensor has ambient light rejection features but it is still best to orient it away from the influence of direct sunlight Shading may be required in some installations to totally protect from sunlight interference e Nearly all exposed parts of the instrument are made of Delrin a strong but soft plastic Always pad the parts of the OBS500 housing that will contact metal or other hard objects with electrical tape or neoprene e Mounting inside the end of a PVC pipe is a convenient way to pr
57. scatter and sidescatter measurements Other diagnostic information is available see Table 7 7 including the raw voltage output from the backscatter and sidescatter sensors the current to open and close the shutter an open and close position count total open and close cycles and a moisture alarm The OBS500 is shipped from the factory to output turbidity in TU and temperature in degrees Celsius The analogue output supports backscatter and or sidescatter according to the status of a control line User Manual 5 4 Vertical Cavity Surface Emitting Laser Diode OBS500 sensors detect suspended matter in water and turbidity from the relative intensity of light backscattered at angles ranging from 125 to 170 and at 90 for the sidescatter measurement A 3D schematic of the main components of the sensor is shown in Figure 5 2 The OBS500 light source is a Vertical Cavity Surface Emitting Laser diode VCSEL which converts 5 mA of electrical current to 2000 uW of optical power The detectors are low drift silicon photodiodes with enhanced NIR responsivity NIR responsivity is the ratio of electrical current produced per unit of light power in A W A light baffle prevents direct illumination of the detector by the light source and in phase coupling that would otherwise produce large signal biases A daylight rejection filter blocks visible light in the solar spectrum and reduces ambient light interference In addition to the filter a synchronous de
58. see se ee ee ee Ge Se ke ee 35 86 RC ER RE RR RE HE ann 36 8 7 Bubbles and Plankton eee se ee Ge ee ee ee ee ee Ge Se Re ee 36 9 Maintenance ee REGEER SEER O 10 Troubleshooting use OG 11 References i e ss a ieee cence AO Appendices A Importing Short Cut Code A 1 A l Importing Short Cut Code into a Program Editor A 1 A T IL CRB asic Datalogger a een sense ee A 1 AN Ela A 2 B Example Programs esse ee ee ee ee ees see ee ee ee ees Bo B 1 CRI000 SDI 12 Program i B 1 B 2 CR1000 RS 232 Program se se se Ge ee Ge Gee ee ee se ee ee B 2 B 3 CR1000 Analogue Program i B 3 B 4 Examples for High Sediment Loads se see cee ee se ee ee B 4 B 4 1 Normally Open CR1000 Example n B 4 B 4 2 Cycle Shutter Wiper for Each Measurement CR1000 Program ER EE OE ER ES OR EG B 5 C OBS500 Copper Sleeve Kit Installation C 1 D SDI 12 and RS 232 Measurement Commands for OS Version 1 ese eke seke ee ee ee ee ees ee ee ene DA d Figures 4 1 Use strain relief to keep stress off the cable and provide extra ele OE N N N EG 3 4 2 Apply tape to protect SenSor c iii 4 4 3 Secure with hose clamps Do not overtighten se 4 4 4 Place and secure mounting fixture i 5 5 1 Drawing of th
59. setup of the OBS500 Select the Terminal tab Click in the Terminal window and push the Enter key several times This will wake up the RS 232 mode of the sensor Once successfully connected you will see an OBS 500 gt prompt Figure 7 2 shows DevConfig after pressing I one to identify the OBS500 By default the OBS500 is in the SDI 12 mode for communication Once in the RS 232 mode if there is no communication for 20 seconds the sensor will return to the SDI 12 mode Device Configui File Backup Options Help Device Type Settings Editor Send OS Terminal COM320 a OBS 500 OBS_500 gt 1 El Sensor serial number 1009 CRS451 Series sdi 12 address 0 CS120 Window position count 20800 CS125 vesel drive 40000 final stage hardware gain obs amp iso 11 CS140 fits counts obs coef 5 data 7 iso coef 4 data 7 CS450 Series offsets obs amp iso 0 002662 0 023437 CS451 Series soft_gain obs amp iso 1 000000 1 000000 CS650 Series ODS raw co ooooo 0 042858 volts iso_90deg raw 0 018457 volts EC100 boot os amp coef sig Oxbef7 0x44de 0x9018 TGA100A TGA200 OBS_500 gt H m El Unknown Unknown I El Wireless Sensor CWB100 CWS220 CWS655 CWS900 Communication Port COM24 Use IP Connection Baud Rate 9600 nubi 1 read raw obs 90deg volts boot sig os sig Echo Input Pause Start Export
60. spended Sediment Measurements Like all other optical turbidity monitors the response depends on the size composition and shape of suspended particles For this reason for monitoring concentrations the sensor must be calibrated with suspended sediments from the waters to be monitored There is no standard turbidimeter design or universal formula for converting TU values to physical units such as mg l or ppm TU values have no intrinsic physical chemical or biological significance However empirical correlations between turbidity and environmental conditions established through field calibration can be useful in water quality investigations The USGS has an excellent chapter 6 on turbidity measurements in their National Field Manual for the Collection of Water Quality Data http water usgs gov owg FieldManual Chapter6 Section6 7_v2 1 pdf Historically most turbidity sensor manufacturers and sensor users labelled the units NTUs for Nephelometric Turbidity Units ASTM and the USGS have come up with the following unit classifications that are applicable to the OBS500 Optical Backscatter FBU Formazin Backscatter Unit Sidescatter FNU Formazin Nephelometric Unit Ratio Back and Sidescatter FNRU Formazin Nephelometric Ratio Unit OBS500 Smart Turbidity Meter with ClearSensor Technology 10 The document U S Geological Survey Implements New Turbidity Data Reporting Procedures details the units http water usgs
61. t data bs median bs mean bs standard deviation bs minimum bs maximum ss median ss mean ss standard deviation ss minimum ss maximum obs tu ss tu ratio tu temperature C raw obs V raw ss V open current mA close current mA wet dry 0 dry 1 wet open wiper position count open max current count open timeout count open current mA total open close count obs tu ss tu temperature C wet dry 0 dry 1 wet User Manual Table 7 7 SDI 12 and RS 232 Measurement Commands for OS Version 2 or Higher aC5 Measure Send Data Measure Send Data Close Wiper Send Data Measure Send Data Close Open Send Data burst data bs median bs mean bs standard deviation bs minimum bs maximum ss median ss mean ss standard deviation ss minimum ss maximum obs tu ss tu ratio tu temperature C raw obs V raw ss V open current mA close current mA wet dry 0 dry 1 wet close wiper position count close max current count close timeout count close current mA total open close count raw burst data V bs median bs mean bs Standard deviation bs minimum bs maximum ss median ss mean ss standard deviation ss minimum ss maximum total open close count open wiper position count open max current count open timeout count close wiper position count close max current count close timeout count 19 OBS500 Smart Turbidity Meter wit
62. t least yearly check electrical ground connections WHILE EVERY ATTEMPT IS MADE TO EMBODY THE HIGHEST DEGREE OF SAFETY IN ALL CAMPBELL SCIENTIFIC PRODUCTS THE CUSTOMER ASSUMES ALL RISK FROM ANY INJURY RESULTING FROM IMPROPER INSTALLATION USE OR MAINTENANCE OF TRIPODS TOWERS OR ATTACHMENTS TO TRIPODS AND TOWERS SUCH AS SENSORS CROSSARMS ENCLOSURES ANTENNAS ETC Contents PDF viewers These page numbers refer to the printed version of this document Use the PDF reader bookmarks tab for links to specific sections 1 Introduction atado 1 2 Cautionary Statements unnnnsnnnnannnnnnnennnnnnnnnnnn 1 3 Initial INSPECTION ee ee EE RE ER RR RR Re eene aa ee ee 2 3 1 Ships EL EE drid N 2 4 HQC STAN iS alla 4 1 Mounting SuggestionS ie 2 4 2 Datalogger Programming and Wiring i 6 5 O lo 5 1 DES USE EE EE a E NES 9 932 Turbidity Units SES EER un 9 5 3 Measurement Details PREKE aerei 10 5 4 Vertical Cavity Surface Emitting Laser Diode 11 6 Specifications iii 7 Installation GG 12 7 1 Default Setnss is ct seien RA a es 12 7 2 Device Configuration Utility iii 13 7 3 Datalogger RTU Connection i 15 1 31 SDI 12 Wide 16 1 32 R 232 Win ui 16 7 3 3 Analogue 0 to 5 Volt Wiring se se Se Se AA Re ee ee 17 TA Communication Modes se ee ee ee Ge ee Se GR RA Ge ee ee 17
63. tection circuit is used to eliminate the bias caused by ambient light The VCSEL is driven by a temperature compensated Voltage Controlled Current Source VCCS OBS Detector al 90 Sidescatter Detector Cone Figure 5 2 Orientation of emitter cone source beam and OBS and sidescatter detector acceptance cones The beam divergence angle of the VCSEL source is 4 worst case and 2 typical 95 of the beam power is contained within a 5 cone 6 Specifications Features Dual backscatter and sidescatter sensors used to measure turbidity ClearSensor antifouling method for better measurements in biologically active water Shutter wiper mechanism keeps lenses clean Refillable biocide chamber prevents fouling Disposable plastic sleeve facilitates cleanup Optional copper sleeve for additional protection especially for sea water or disposable plastic sleeve facilitates easy cleanup Compatible with Campbell Scientific CRBasic dataloggers CR6 CR200 X series CR800 series CR1000 CR3000 and CR5000 Also compatible with Edlog dataloggers CR500 CR510 CR10 X and CR23X Dual Probe Backscatter and 90 degree sidescatter TU Range 0 to 4000 TU 11 OBS500 Smart Turbidity Meter with ClearSensor Technology 7 12 7 1 Installation Active and Passive Antifouling Accuracy Temperature Accuracy Temperature Range Storage Temperature Emitter Wavelength Power Requirements Power Consumption
64. truction User Manual The following three tests are used to diagnose malfunctions of an OBS500 1 The Finger Wave Test is used to determine if an OBS sensor is alive Power the OBS sensor and connect datalogger see Section 7 2 Device Configuration Utility Wave your finger across the sensor window about 20 mm away from it The datalogger should show the output fluctuating from a few TU to the full scale signal If there are no signal fluctuations of this order there is a problem that requires attention 2 The Shake Test is done to determine if water has leaked inside the pressure housing Unplug the cable and gently shake the sensor next to your ear and listen for sloshing water This test gives a false negative result when the amount of water in the housing is large enough to destroy the circuit but too small to be audible 3 A Calibration Check is done to verify if a working OBS sensor needs to be recalibrated In order to be meaningful the user must have a criterion for this test For example this criterion might be 5 The sensor is placed in calibration standards with the 1 and 2 TU values listed in Figure 7 5 and the datalogger readings are logged If either reading differs by more than 5 from ones reported on the factory calibration certificate or the user s own calibration data the sensor should be recalibrated If the first two calibration points fall within the acceptance criterion then the third value can be t
65. ttp water usgs gov owq turbidity TurbidityInfoSheet pdf Appendix A Importing Short Cut Code This tutorial shows e How to import a Short Cut program into a program editor for additional refinement e How to import a wiring diagram from Short Cut into the comments of a custom program A 1 Importing Short Cut Code into a Program Editor Short Cut creates files that can be imported into either CRBasic Editor or Edlog program editor These files normally reside in the C campbellsci SCWin folder and have the following extensions DEF wiring and memory usage information CR2 CR200 X datalogger code CR1 CR1000 datalogger code CR8 CR800 datalogger code CR3 CR3000 datalogger code CR5 CR5000 datalogger code DLD contain code for CR10 X CR23X CR500 or CR510 dataloggers The following procedures show how to import these files for editing A 1 1 CRBasic Datalogger Use the following procedure to import Short Cut code into CRBasic Editor CR200 X CR1000 CR800 CR3000 CR5000 dataloggers NOTE 1 Create the Short Cut program following the procedure in Section 4 Quickstart Finish the program and exit Short Cut Make note of the file name used when saving the Short Cut program Open CRBasic Editor Click File Open Assuming the default paths were used when Short Cut was installed navigate to C CampbellSci SCWin folder The file of interest has a CR2 CR1 CR8 CR3 or
66. ummarizes some of the factors that affect OBS measurements and shows how ignoring them can lead to erroneous data If you are certain that the characteristics of suspended matter will not change during your survey and that your OBS was factory calibrated with sediment from your survey site you only need to skim this section to confirm that no problems have been overlooked Particle Size The size of suspended sediment particles typically ranges from about 0 2 to 500 um in surface water streams estuaries and the ocean With size shape and colour remaining constant particle area normal to a light beam will determine the intensity of light scattered by a volume of suspended matter Results of tests with sediment shown in Figure 8 1 indicate a wide range of sensitivity is associated with fine mud and coarse sand about two orders of magnitude The significance of these results is that size variations between the field and laboratory and within a survey area during monitoring will produce shifts in apparent TU and SSC values that are unrelated to real changes in sediment concentration Figure 8 2 shows the difference in apparent turbidity that can result from different ways of disaggregating sediment User Manual 1 00 0 10 OBS Sensitivty S mV per mg I 0 01 10 0 100 0 1000 0 Median Particle Size D Figure 8 1 Normalized sensitivity as a function of grain diameter 60 Sonic Probe 40 Most Aggressiv
67. utive number 3 Inthe Start Address field type in the number of the first input location 4 Inthe Number of InLocs field type in 2 and select OK 7 7 Operation in High Sediment Loads and Sandy Sediments NOTE Sites with high sediment loads and large sand grains can be problematic for the shutter and it s motor The recommendations provided in this section should help reduce these problems Typically sites with high biological growth have relatively low sediment loads 29 OBS500 Smart Turbidity Meter with ClearSensor Technology 30 Run the OBS500 in a normally open mode For example close then open the wiper once every four hours This reduces the wear on the motor significantly and save power The interval can be adjusted over time Increase the interval if experiencing fouling If the windows are staying clean slow it down even more Example CRBasic programs are provided at Appendix B 4 Examples for High Sediment Loads a M3 opens the wiper b M4 M5 or M6 perform measurements when the wiper is open c M7 closes the wiper Clean the shutter assembly The frequency that the shutter should be cleaned depends on the sediment load and can vary from weeks to months step 3 can help you determine the required frequency for cleaning Two levels of cleaning should be done a flush the wiper as it opens and closes with a stream of clean water or b remove the wiper from the OBS500 by removing one screw and f
68. wiper SDI12Recorder obsDatClose 1 0 M7 1 0 Close wiper Open 0 Else if closed SDI12Recorder obsDatOpen 1 0 M3 1 0 Open wiper Delay 8 11 Sec SDI12Recorder 0BS500 1 0 M4 1 0 Measure without moving the wiper Open 1 EndIf Call Output Tables CallTable Test NextScan EndProg B 5 Appendix B Example Programs B 6 Appendix C OBS500 Copper Sleeve Kit Installation 1 Remove the Button Head Hex Screw as shown 2 Slide the Copper Sleeve over the OBS500 and snap it into place C 1 Appendix D SDI 12 and RS 232 Measurement Commands for OS Version 1 OBS500 OS version 1 supports different commands than newer operation systems Table D 1 shows the commands available for OS version 1 Use the al SDI 12 command or use DevConfig to see the OS version downloaded to your OBS500 The OS version can be updated by using DevConfig Table D 1 SDI 12 and RS 232 Measurement Commands aM aC a address Open Wiper Measure Close Send Data Open Wiper Measure Close Send Data Open Wiper Measure Close Send Data Open Wiper Send Data Measure Send Data Measure Send Data Measure Send Data obs tu ss tu temperature degc wet dry 0 dry 1 wet ratio tu temperature degc wet dry 0 dry 1 wet obs tu ss tu ratio tu temperature degc raw obs volts raw ss volts open current ma close current ma wet dry 0 dry 1 wet open wipe

OBS500 Smart Turbidity Meter with ClearSensor™ Technology

Contents

Download Pdf Manuals

Related Search

Related Contents

OBS500 Smart Turbidity Meter with ClearSensor&trade; Technology

Contents

Download Pdf Manuals

Related Search

Related Contents

OBS500 Smart Turbidity Meter with ClearSensor™ Technology