Campbell OBS-3+ User Manual Download

Page: 1 / 52

OBS-3+ and

OBS300

Suspended Solids and

Turbidity Monitors

Revision: 7/19

Campbell Scientific

Summary of Contents for OBS-3+

Page 2: ......

Page 3: ...under guarantee or not Please state the faults as clearly as possible and if the product is out of the guarantee period it should be accompanied by a purchase order Quotations for repairs can be give...

Page 4: ......

Page 5: ...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 marke...

Page 6: ......

Page 7: ...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 cl...

Page 8: ......

Page 9: ...ement Details 6 6 Specifications 7 7 Installation 9 7 1 Pre Deployment Tests 9 7 2 Mounting Considerations 9 7 2 1 Siting 9 7 2 2 Mounting Options 9 7 2 2 1 PVC Pipe 9 7 2 2 2 Cable Ties or Hose Clamp...

Page 10: ...entation source beam and detector acceptance cone of the OBS 3 top right and OBS300 bottom right 6 7 1 OBS 3 connected to a CR1000 data logger OBS300 has the same wiring 11 7 2 Calibration certificate...

Page 11: ...ay and a data logger D 1 Tables 7 1 Wire Colour Function and Data Logger Connection 10 8 1 SDVB NTU values for turbidity calibrations in standard low ranges 15 8 2 Change in NTU value resulting from o...

Page 12: ......

Page 13: ...ee an older manual at www campbellsci com old manuals 2 Precautions READ AND UNDERSTAND the Safety section at the front of this manual Although the OBS 3 and OBS300 are rugged they should be handled a...

Page 14: ...d see Section 8 Calibration p 14 3 Refer to Section 7 2 Mounting Considerations p 9 for siting and mounting options 4 2 Use SCWin to Program Data Logger and Generate Wiring Diagram A video that descri...

Page 15: ...sensor Low and High NTU Range and Maximum Voltage Output You can use the default value V for the Coefficients based on signal voltage in units of Enter the Low Range Coefficients and High Range Coeffi...

Page 16: ...ut of the sensor in LoggerNet PC400 RTDAQ or PC200W to make sure it is making reasonable measurements 5 Overview The heart of an OBS sensor is a near infrared NIR laser and photodiode for detecting th...

Page 17: ...scattering measurements made on calibration standards such as Formazin StablCal or SDVB Turbidity is caused by suspended and dissolved matter such as sediment plankton bacteria viruses and organic and...

Page 18: ...minate the bias caused by ambient light The VCSEL is driven by a temperature compensated voltage controlled current source VCCS The interface between the optics and the water sample is a window made o...

Page 19: ...he device exactly as it will be used The reason for this is that the factory calibration is performed with a NIST traceable digital multimeter and the numerical values reported by some host devices no...

Page 20: ...Optical power 2000 W Drift 2 per year Daylight rejection 28 dB re 48 mW cm 2 Maximum data rate 10 Hz Minimum warm up time 2 s Maximum depth Stainless steel body 500 m 1640 5 ft Titanium body 1500 m 49...

Page 21: ...es and repeat the test The results should be similar 7 2 Mounting Considerations Schemes for mounting the OBS 3 and OBS300 will vary with applications however the same basic precautions should be foll...

Page 22: ...ed by other companies is similar In this configuration single ended analogue inputs are used to measure the OBS voltage signal The red power wire is connected to a switched 12 V terminal which allows...

Page 23: ...needs are more complex the files that Short Cut creates are a great source for programming code to start a new program or add to an existing custom program Short Cut cannot edit programs after they ar...

Page 24: ...libration curve in units of both millivolts and volts see Section 7 5 Calibration Certificate p 12 If using the voltage curve coefficients the multiplier for the singe ended voltage instruction needs...

Page 25: ...3 and OBS300 Suspended Solids and Turbidity Monitors 13 FIGURE 7 2 Calibration certificate showing millivolt coefficients Curve Type Polynomial for Converting to NTU Polynomial for Converting to NTU...

Page 26: ...tyrene divinylbenzene beads SDVB turbidity over the range from 0 to 4000 NTU is shown on FIGURE 8 1 As shown on the inset the response function is contained within region A the linear region of the un...

Page 27: ...ty meter cannot be used to calibrate a different model The standard values for calibrating OBSs are 125 NTU GFS Part No 8428 250 NTU GFS Part No 8429 500 NTU GFS Part No 8430 1000 NTU GFS Part No 8431...

Page 28: ...he dilution procedures the uncertainty in the NTU value of an SDVB standard is 1 of the value indicated on the standard bottle Consequently the NTU value of one litre of standard in an uncovered 100 m...

Page 29: ...n log sheet 2 Swap the multimeter red test probe to the high range output wire white or connect the white wire to the data logger instead of the blue wire and record a 10 second average of the high ra...

Page 30: ...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 Alteratio...

Page 31: ...ion where the OBS sensor will be used sediment should be in a state where grinding sieving or pulverization does not change its particle size distribution Averaging multimeter or data logger 12 V gel...

Page 32: ...at 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 wi...

Page 33: ...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 slos...

Page 34: ...A Scotch Brite scouring pad works well for most types of window fouling First wet the pad and then place it on a counter with a plastic laminate top so that the side of the pad is aligned with the ed...

Page 35: ...h 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 on...

Page 36: ...o do is to take a lot of water samples and analyze them in the laboratory This is not always practical during storms when the errors are likely to be largest Do not rely solely on OBS sensors to monit...

Page 37: ...the particle and the detector that backscatter decreases exponentially with increasing sediment concentration For mud this occurs at concentrations greater than about 5000 mg L 1 FIGURE 11 4 shows a...

Page 38: ...d 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 OBS signal on a mass concentration basis...

Page 39: ...errors 11 7 Bubbles and Plankton Although bubbles efficiently scatter light monitoring in most natural environments shows that OBS signals are not strongly affected by bubbles Bubbles and quartz parti...

Page 40: ...tific sells two wipers from a third party manufacturer the Hydro Wiper C with its own controller or the Hydro Wiper D that is controlled by a data logger 12 References Bohren C F and D H Huffman Absor...

Page 41: ...or measurement procedure that produce unintended and unknown shifts in turbidity or SSC Sample Volume The water volume where the OBS infrared beam and suspended particles interact and the scattered l...

Page 42: ...oncentration of dissolved light absorbing matter increases turbidity will decrease Turbidity operational definition NTU value is a number ranging from 0 to 10 000 that is computed by a turbidimeter fr...

Page 43: ...he CRBasic program This program can now be edited for additional refinement Once the file is edited with CRBasic Editor Short Cut can no longer be used to edit the program it created 2 To add the Shor...

Page 44: ......

Page 45: ...ine Data Tables DataTable Data_15m 1 1 DataInterval 0 15 Min 10 Sample 1 NTU FP2 EndTable Main Program BeginProg Declare Constants n 21 A 1 0 24763 B 1 105 69 C 1 0 29928 A 2 35 310 B 2 401 11 C 2 0 2...

Page 46: ...ogram The following example uses the voltage curve of the calibrations certificate provided in FIGURE 7 3 Since the coefficients of the voltage curve are used the multiplier for the VoltSE instruction...

Page 47: ...are from the voltage calibration sheet VoltSe NTUarray i 1 2 0 001 0 NTUarray i A 2 NTUarray i 2 B 2 NTUarray i C 2 Next i AvgSpa NTU 10 NTUarray StdDevSpa NTU_SD 10 NTUarray If NTU 250 Then For i 1 T...

Page 48: ......

Page 49: ...be concerned with the wire colours for the 8425 cable as the MCBH wires are not accessible When a custom cable assembly is purchased from a third party vendor to connect the OBS sensor to a current m...

Page 50: ...r OBS sensor bulkhead connectors MCBH 5 FS MCIL 5 MP Contact Number Electrical Function Wire Colour MCBH Wire Colour 8425 1 Power 5 15V Red Red 2 Power Ground Black Black 3 Signal Common Green Green 4...

Page 51: ...the switched 12V terminal FIGURE D 1 shows the relay connections 12V C1 G G SE1 SE2 AG Black White Blue Green FIGURE D 1 Wiring diagram for connecting an OBS sensor to an external relay and a data log...

Page 52: ...cc Website www campbellsci cc France Location Vincennes France Phone 0033 0 1 56 45 15 20 Email info campbellsci fr Website www campbellsci fr Germany Location Bremen Germany Phone 49 0 421 460974 0...

Search results

Summary of Contents for OBS-3+

Reviews:

Related manuals for OBS-3+

Brands by name

Popular brands

Campbell OBS-3+, Product Manual

Search results

Summary of Contents for OBS-3+

Reviews:

Related manuals for OBS-3+

Brands by name

Popular brands