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OBS500 Smart Turbidity Meter with ClearSensor

Technology

TABLE 7-1. Factory Settings

SDI-12/Analog

SDI-12

SDI-12 Address

RS-232 Baud Rate

9600

Turbidity units

Temperature units

Celsius

7.2

Device Configuration Utility

The

Device Configuration Utility

(

DevConfig

) is used to change settings, set up

the analog sensor, 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.

The OBS500 is supported in

DevConfig

version 1.16 or higher.

FIGURE 7-1. Device Configuration Utility

NOTE

Summary of Contents for OBS500

Page 1: ...OPERATOR S MANUAL OBS500 Smart Turbidity Meter with ClearSensor Technology Revision 1 16 C o p y r i g h t 2 0 0 8 2 0 1 6 C a m p b e l l S c i e n t i f i c I n c ...

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Page 3: ...ducts to CSI CSI will return such Products by surface carrier prepaid within the continental United States of America To all other locations CSI will return such Products best way CIP port of entry per Incoterms 2010 This warranty shall not apply to any Products which have been subjected to modification misuse neglect improper service accidents of nature or shipping damage This warranty is in lieu...

Page 4: ...ng container Campbell Scientific s shipping address is CAMPBELL SCIENTIFIC INC RMA _____ 815 West 1800 North Logan Utah 84321 1784 For all returns the customer must fill out a Statement of Product Cleanliness and Decontamination form and comply with the requirements specified in it The form is available from our website at www campbellsci com repair A completed form must be either emailed to repai...

Page 5: ...e beginning work Wear a hardhat and eye protection and take other appropriate safety precautions while working on or around tripods and towers 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 Use only manufacturer recommended parts materials and tools Utility and Electrical You can be kil...

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Page 7: ...efault Settings 12 7 2 Device Configuration Utility 13 7 3 Datalogger RTU Connection 16 7 3 1 SDI 12 Wiring 17 7 3 2 RS 232 Wiring 17 7 3 3 Analog 0 to 5 Volt Wiring 18 7 4 Communication Modes 18 7 4 1 SDI 12 18 7 4 1 1 SDI 12 Addresses 20 7 4 1 2 SDI 12 Transparent Mode 20 7 4 2 RS 232 21 7 5 Calibration 22 7 5 1 Turbidity 22 7 5 2 Sediment 26 7 5 2 1 Dry Sediment Calibration 26 7 5 2 2 Wet Sedim...

Page 8: ... B 4 B 4 2 Cycle Shutter Wiper for Each Measurement CR1000 ProgramB 5 C OBS500 Copper Sleeve Kit Installation C 1 D SDI 12 and RS 232 Measurement Commands for OS Version 1 D 1 Figures 4 1 Use strain relief to keep stress off the cable and provide extra security 3 4 2 Apply tape to protect sensor 4 4 3 Secure with hose clamps Do not overtighten 4 4 4 Place and secure mounting fixture 5 5 1 Drawing ...

Page 9: ... wide range of SSC 35 8 5 Infrared reflectivity of minerals as a function of 10 Munzell Value 36 9 1 DevConfig Send OS 38 Tables 7 1 Factory Settings 13 7 2 RS 232 Terminal Commands 15 7 3 OBS500 Connector Pin Out 16 7 4 SDI 12 Wiring 17 7 5 RS 232 Wiring 17 7 6 Analog 0 5 Volt Wiring 18 7 7 SDI 12 and RS 232 Measurement Commands for OS Version 2 or Higher 19 7 8 RS 232 Settings 22 7 9 Calibration...

Page 10: ...Table of Contents iv ...

Page 11: ...istance 2 Precautions READ AND UNDERSTAND the Safety section at the front of this manual 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 The sensor may be damaged if it is encased in ice Damages caused by freezing conditions will not be covered by our warranty Campbell Scientific recommends removing the sensor from the wa...

Page 12: ... 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 c...

Page 13: ...trong but soft plastic Always pad the parts of the OBS500 housing that will contact metal or other hard objects with electrical tape or neoprene Mounting inside the end of a PVC pipe is a convenient way to provide 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 st...

Page 14: ...OBS500 Smart Turbidity Meter with ClearSensor Technology 4 FIGURE 4 2 Apply tape to protect sensor FIGURE 4 3 Secure with hose clamps Do not overtighten ...

Page 15: ...OBS500 Smart Turbidity Meter with ClearSensor Technology 5 FIGURE 4 4 Place and secure mounting fixture ...

Page 16: ...atalogger wiring terminals Short Cut is available as a download on www campbellsci com and the ResourceDVD It is included in installations of LoggerNet PC200W PC400 or RTDAQ The following procedure shows using Short Cut to program the OBS500 1 Open Short Cut and select New Program 2 Select Datalogger Model and Scan Interval default of 5 seconds is OK for most applications Click Next ...

Page 17: ...changed by clicking the Temperature or Measure Sensor box and selecting a different option Typically the default SDI 12 address of 0 is used 4 After selecting the sensor click Wiring Diagram to see how the sensor is to be wired to the datalogger The wiring diagram can be printed now or after more sensors are added 5 Select any other sensors you have then finish the remaining Short Cut steps to com...

Page 18: ...eir unique optical design U S Patent No 4 841 157 backscatter sensors perform better than most in situ turbidity monitors in the following ways Measure turbidity to 4000 TU compared to 1200 TU typically for sidescatter sensors Insensitivity to bubbles and organic matter Ambient light rejection Low temperature coefficient Sidescatter sensors have the following advantages More accurate in very clean...

Page 19: ...or 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 ...

Page 20: ...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 analog 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 me...

Page 21: ...CSEL is driven by a temperature compensated Voltage Controlled Current Source VCCS 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 turbidi...

Page 22: ...5 s Measurement Time 2 s Outputs SDI 12 version 1 3 1200 bps RS 232 9600 bps 8 data bits 1 stop bit no parity no flow control Analog 0 to 5 Volts Submersion Depth 100 m 328 ft Diameter 4 76 cm 1 875 in Length 27 cm 10 625 in Weight 0 52 kg 1 15 lb Maximum Cable Length 460 m 1500 ft 1 channel SDI 12 or Analog 15 m 50 ft RS 232 7 Installation If you are programming your datalogger with Short Cut ski...

Page 23: ...up the analog sensor 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 The...

Page 24: ...he 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 prompt FIGURE 7 2 shows DevConfig after pressing l 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...

Page 25: ... 12 address etc 2 Open Wiper Command to open wiper started please wait Wiper now open average current was xxx mA 3 Close Wiper Command to close wiper started please wait Wiper now closed average current was xxx mA H or h Help menu DevConfig allows you to change the configuration of the OBS500 Select the Settings Editor tab FIGURE 7 3 Settings Editor screen ...

Page 26: ...d the electrical functions and wire colors TABLE 7 3 OBS500 Connector Pin Out MCIL 8 MP MCBH 8 FS Contact Number Electrical Function Wire Color 1 Power Ground Black 2 SDI 12 RS232 TX Analog SS BS Control White 3 Power 9 6 to 15 V Red 4 Analog Signal Green 5 RS 232 RX Shutter Open Blue 6 NC 7 Analog Ground Brown 8 NC No Connection Clear Braid This document provides the recommended wiring configurat...

Page 27: ... G G 1 Only odd control ports or universal channels can be used for SDI 12 for example C1 C3 7 3 2 RS 232 Wiring Our CR800 CR850 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 TABLE 7 5 RS 232 Wiring Color OBS500 Function Connection RS 232 9 pin...

Page 28: ...ngle ended Differential measurements are recommended The output is scaled as 1 mV 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 communica...

Page 29: ...C2 Open Wiper Measure Close Send Data obs tu ss tu ratio tu temperature ºC raw obs V raw ss V open current mA close current mA wet dry 0 dry 1 wet aM3 aC3 Open Wiper Send Data open wiper position count open max current count open timeout count open current mA total open close count aM4 aC4 Measure Send Data obs tu ss tu temperature ºC wet dry 0 dry 1 wet aC5 Burst Data Measure 100 Times Send Data ...

Page 30: ...I 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 ...

Page 31: ... dataloggers press Enter until the datalogger responds with the prompt e g CR1000 for the CR1000 Type SDI12 at the prompt and press Enter 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 b...

Page 32: ...mpbell Scientific for the two year service We recommend checking the calibration in the field as described below If a 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 ...

Page 33: ...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 TABLE 7 9 Calibration Materials and Volumes Sidescatter 90 Degree Materials Calibration Cup Diameter mm inches 8594 20TU 100 4 8595 40TU 100 4 8596 125TU 100 4 8597 250TU 100 4 8598 500TU 100 4 8599 1000TU 100 4 OBS Sensor Material 8600 1...

Page 34: ... 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 liter 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 e...

Page 35: ... 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 2nd order polynomial regressions on the calibration data to get the coefficients f...

Page 36: ...ined accurately with an electronic 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 r...

Page 37: ...ng 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 ...

Page 38: ... computer or datalogger and enter them on the calibration log sheet 7 Calculate the sediment weight increment 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 8 Add enough additional sediment to get one full increment of sed...

Page 39: ...degrees C The SDI12Recorder instruction has the following form SDI12Recorder Destination Output String Multiplier Offset Refer to Appendix B 1 CR1000 SDI 12 Program p B 1 for an example of using this CRBasic instruction 7 6 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 CR100...

Page 40: ... the OBS500 by removing one screw and follow the directions provided in Section 7 7 1 Wiper Removal Procedure p 30 Flush and clean 3 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 ...

Page 41: ...dity Meter with ClearSensor Technology 31 FIGURE 7 9 Remove the screw FIGURE 7 10 Insert screwdriver and rotate clockwise FIGURE 7 11 Shutter disassembled Remove 4 40 flat head screw Copper plate Drive shaft access port ...

Page 42: ...anges from about 0 2 to 500 μm in surface water streams estuaries and the ocean With size shape and color 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 magnit...

Page 43: ...article Size D50 0 01 0 10 1 00 OBS Sensitivty S mV per mg l 1 S 1 D50 FIGURE 8 1 Normalized sensitivity as a function of grain diameter FIGURE 8 2 The apparent change in turbidity resulting from disaggregation methods Sonic Probe Most Aggressive Hand Shaking Least Aggressive Sonic Bath ...

Page 44: ...ely 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...

Page 45: ...SC values of either 3 000 or 33 000 mg l Factory calibrations are performed in the linear region designated A on the graph FIGURE 8 4 Response of an OBS sensor to a wide range of SSC 8 5 IR Reflectivity Sediment Color Infrared reflectivity indicated by sediment color has a major effect on sensitivity because with other factors remaining constant it changes the intensity of light scattering Althoug...

Page 46: ...roduce 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 ...

Page 47: ...yed 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 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 th...

Page 48: ...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 instruction ...

Page 49: ...r this test For example this criterion might be 5 The sensor is placed in calibration standards with the 1st and 2nd 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 with...

Page 50: ...m 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 http water usgs ...

Page 51: ... program and exit Short Cut Make note of the file name used when saving the Short Cut program 2 Open CRBasic Editor 3 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 the CR6 CR2 CR1 CR8 CR3 or CR5 extension Select the file and click Open 4 Immediately save the file in a folder different from C Campbel...

Page 52: ...Appendix A Importing Short Cut Code Into CRBasic Editor A 2 This character instructs the datalogger compiler to ignore the line when compiling ...

Page 53: ...talogger 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 OBS FP2 Sample 1 SS FP2 Sample 1 Temp FP2 Sample 1 WetDry FP2 EndTable Main Program BeginProg Scan 30 Sec 0 0 SDI12Recorder SDI 1 0 M 1 0 0 Call Output Tables CallTable Test NextScan EndP...

Page 54: ...SerialOpen Com1 9600 0 0 150 Scan 30 Sec 0 0 OutString2 CHR 13 a series of carriage returns will put OBS500 into RS 232 mode OutString 0M CHR 13 address and then use commands M to M8 Send String over communication port C1 COM1 TX SerialOut Com1 OutString2 OBS_500 15 100 put OBS500 into RS232 mode delay 1 1 Sec SerialOut Com1 OutString 0 1000 send command Receive String over communication port C1 C...

Page 55: ...its obs NTU Units ss NTU DataTable OBS500_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 0 or ss 1 Delay 0 9500 msec 6 secs shutter open 3 5 secs VoltDiff obs...

Page 56: ...ipped 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 ...

Page 57: ...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 stripp...

Page 58: ...Appendix B Example Programs B 6 ...

Page 59: ...C 1 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 3 Install the 4 40 x SS Slot Head Screw ...

Page 60: ...Appendix C OBS500 Copper Sleeve Kit Installation C 2 ...

Page 61: ...eturned aM aC a address Open Wiper Measure Close Send Data obs tu ss tu temperature degc wet dry 0 dry 1 wet aM1 aC1 Open Wiper Measure Close Send Data ratio tu temperature degc wet dry 0 dry 1 wet aM2 aC2 Open Wiper Measure Close Send Data 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 aM3 aC3 Open Wiper Send Data open wiper ...

Page 62: ...rd 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...

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Page 64: ...Rua Apinagés nbr 2018 Perdizes CEP 01258 00 São Paulo SP BRASIL www campbellsci com br vendas campbellsci com br Campbell Scientific Canada Corp 14532 131 Avenue NW Edmonton AB T5L 4X4 CANADA www campbellsci ca dataloggers campbellsci ca Campbell Scientific Centro Caribe S A 300 N Cementerio Edificio Breller Santo Domingo Heredia 40305 COSTA RICA www campbellsci cc info campbellsci cc Campbell Sci...

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