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Summary of Contents for Campbell OBS501
- Page 1 OBS501 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 ,...
- Page 3 Limited Warranty “Products manufactured by CSI are warranted by CSI to be free from defects in materials and workmanship under normal use and service for twelve months from the date of shipment unless otherwise specified in the corresponding product manual. (Product manuals are available for review online at www.campbellsci.com.) Products not manufactured by CSI, but that are resold by CSI, are warranted only to the limits extended by the original manufacturer.
- Page 4 SCIENTIFIC, INC., phone (435) 227-9000. After an application engineer determines the nature of the problem, an RMA number will be issued. Please write this number clearly on the outside of the shipping container. Campbell Scientific’s shipping address is: CAMPBELL SCIENTIFIC, INC.
- Page 5 • Periodically (at 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.
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Page 7: Table Of Contents
Applications ..................5 Backscatter and Sidescatter Sensors ............ 5 ® ClearSensor Antifouling Method ............6 Comparison of OBS500 and OBS501 ..........6 6. Specifications ............. 6 7. Installation ..............7 Default Settings ..................8 Device Configuration Utility ..............8 7.2.1 Terminal Tab................. - Page 8 Table of Contents Calibration ..................24 8.6.1 Turbidity..................24 8.6.2 Sediment..................27 8.6.2.1 Dry-Sediment Calibration ..........27 8.6.2.2 Wet-Sediment Calibration ..........28 8.6.2.3 In situ Calibration ............28 8.6.2.4 Performing a Dry-Sediment Calibration ......28 Operation in High Sediment Loads and Sandy Sediments ....30 8.7.1 Wiper Removal Procedure ............
- Page 9 Table of Contents Water Color ..................E-5 Bubbles and Plankton............... E-5 Figures 5-1. OBS501 sensor with the shutter open (top) and closed (bottom) ..6 7-1. Device Configuration Utility..............9 7-2. Terminal Mode using 1 and H commands ......... 10 7-3.
- Page 10 Table of Contents D-1. OBS501 SDI-12 Command and Response Set ........ D-1 CRBasic Examples B-1. CR6 SDI-12 Program ..............B-1 B-2. CR1000 SDI-12 Program ..............B-2 B-3. CR1000 RS-232 Program ..............B-3 B-4. CR1000 Analog Program ..............B-4 B-5. Normally Open CR1000 Example........... B-5 B-6.
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Page 11: Introduction
Safety section at the front of this manual. • The OBS501 needs to be sent in after two years or 70,000 cycles for drive shaft seal replacement. (See aM9! command in TABLE 8-2, SDI-12 and RS-232 Measurement Commands (p. 21) •... -
Page 12: Initial Inspection
, for more information. (p. 30) • Remember that although the OBS501 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. Initial Inspection •... -
Page 13: Quickstart
ResourceDVD. It is included in installations of LoggerNet, PC200W, PC400, or RTDAQ. The following procedure shows using Short Cut to program the OBS501. Open Short Cut and select New Program. Select Datalogger Model and Scan Interval (default of 5 seconds is OK... - Page 14 ® OBS501 Smart Turbidity Meter with ClearSensor Technology Under the Available Sensors and Devices list, select the Sensors | Water | Quality folder. Select OBS500 Smart Turbidity Meter. Click to move the selection to the Selected device window. Temperature defaults to degrees Celsius and the sensor is measured every scan. These can be changed by clicking the Temperature or Measure Sensor box and selecting a different option.
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Page 15: Overview
Tracking water-well completion including development and use Backscatter and Sidescatter Sensors The heart of the OBS501 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. -
Page 16: Clearsensor Antifouling Method
The OBS501 can sense if the shutter’s motor is working harder than normal. If it is, the shutter moves slightly back and forth to dislodge sand grains before fully opening or closing. -
Page 17: Installation
® OBS501 Smart Turbidity Meter with ClearSensor Technology Dual Probe: Backscatter and 90-degree sidescatter Turbidity Units (TU) Range: 0 to 4000 TU (see Section 8.1, Turbidity Units , for information about (p.18) turbidity units) Active and Passive Antifouling: Shutter, wiper, biocide, copper, optional... -
Page 18: Default Settings
® OBS501 Smart Turbidity Meter with ClearSensor Technology Default Settings The OBS501 is configured at the factory with the default settings shown in TABLE 7-1. For most applications, the default settings are used. TABLE 7-1. Factory Settings SDI-12/Analog SDI-12 SDI-12 Address... -
Page 19: Terminal Tab
Select the correct PC Serial Port and then click Connect (see FIGURE 7-1). 7.2.1 Terminal Tab The Terminal tab can be used to verify the setup of the OBS501. Select the Terminal tab. Click in the Terminal window and select the Enter key several times. -
Page 20: Terminal Mode Using 1 And H Commands
® OBS501 Smart Turbidity Meter with ClearSensor Technology FIGURE 7-2. Terminal Mode using 1 and H commands TABLE 7-2. RS-232 Terminal Commands Terminal Commands Values Returned 1 Identify Serial Number, SDI-12 address, etc. 2 Open Wiper Command to open wiper started – please wait Wiper now open –... -
Page 21: Setting Editor Tab
The SDI-12 address is not used while in analog mode. 7.2.3 Downloading a New Operating System DevConfig is used to download a new operating system to the OBS501. Select the Send OS tab and follow the directions on the screen. -
Page 22: Datalogger/Rtu Connection
OBS501 Smart Turbidity Meter with ClearSensor Technology FIGURE 7-4. DevConfig, Send OS Datalogger/RTU Connection The OBS500CBL-L Field Cable connects the OBS501 to a datalogger or RTU (see Section 8.3, OBS500CBL-L Connector Pin Out ). TABLE 7-3, SDI- (p. 20) 12 Wiring... -
Page 23: Sdi-12 Wiring
® OBS501 Smart Turbidity Meter with ClearSensor Technology 7.3.1 SDI-12 Wiring TABLE 7-3. SDI-12 Wiring CR800 CR5000 CR3000 CR200X Color Description CR1000 Series Power Battery+ Power Black Ground Control SDI-12 Control Port White Signal Port SDI-12 Universal Channel Brown not used... -
Page 24: Analog 0 To 5 Volt Wiring
® OBS501 Smart Turbidity Meter with ClearSensor Technology 7.3.3 Analog 0 to 5 Volt Wiring TABLE 7-5. Analog 0-5 Volt Wiring CR6, CR800, CR850, Color Description CR1000, CR3000, CR5000 Control Port or Blue Shutter Open - Control High Universal Channel... -
Page 25: Sdi-12
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 OBS501 can see to a distance of about 50 cm (20 in) in very clean water at angles ranging from 125° to... -
Page 26: Mounting Example
• Mounting inside the end of a PVC pipe is a convenient way to provide structure and protection for deployments. The OBS501 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... -
Page 27: Apply Tape To Protect Sensor
® OBS501 Smart Turbidity Meter with ClearSensor Technology FIGURE 7-6. Apply tape to protect sensor FIGURE 7-7. Secure with hose clamps; do not overtighten... -
Page 28: Operation
® OBS501 Smart Turbidity Meter with ClearSensor Technology FIGURE 7-8. Place and secure mounting fixture Operation 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. -
Page 29: Vertical-Cavity Surface-Emitting Laser Diode
125° to 170° and at 90° for the sidescatter measurement. A 3D schematic of the main components of the sensor is shown in FIGURE 8-1. The OBS501 light source is a Vertical-Cavity Surface-Emitting Laser diode (VCSEL), which converts 5 mA of electrical current to 2000 μW of optical power. -
Page 30: Obs500Cbl-L Connector Pin Out
No Connection Clear/Braid Measurements The OBS501 design combines the sensor, analog 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... -
Page 31: Communication Modes
The OBS501 is shipped from the factory to output turbidity in TU and temperature in degrees Celsius. The analog output supports backscatter and/or sidescatter according to the status of a control line. - Page 32 ® OBS501 Smart Turbidity Meter with ClearSensor Technology TABLE 8-2. SDI-12 and RS-232 Measurement Commands Commands Process Values Returned obs (TU) aM2! Open Wiper aC2! Measure ss (TU ) Close ratio (TU) Send Data temperature (ºC) raw obs (V) raw ss (V)
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Page 33: Measuring Multiple Sdi-12 Sensors
, for more information. (p. D-1) 8.5.2 RS-232 RS-232 measurements of the OBS501 are typically made by a CR800, CR850, CR1000, or CR3000 datalogger or an RTU device. The OBS500CBL-L Field Cable is used and wired appropriately for the measurement device. See TABLE 8-3, for settings. -
Page 34: Calibration
8.6.1 Turbidity Field recalibration is not recommended and usually not needed until the OBS501 is sent back to Campbell 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 OBS501 should be sent to Campbell Scientific to perform the calibration. -
Page 35: Calibration Materials And Volumes
Technology ® AMCO Clear SDVB turbidity standards are used to calibrate an OBS501 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 8-4. Calibration Materials and Volumes... -
Page 36: Position Of Obs501 In Clean Tap Water In Big Black Tub
10 s average of the low-range output. Record the average output on the calibration log sheet. FIGURE 8-3. Position of OBS501 in clean tap water in big black tub Pour the first SDVB standard into the appropriately sized cup (see TABLE 8-5). -
Page 37: Sediment
Perform 2 -order polynomial regressions on the calibration data to get the coefficients for converting OBS signals to TU values. ® FIGURE 8-4. OBS501 in 500-TU AMCO Clear turbidity standard in 100-mm black polyethylene calibration cup 8.6.2 Sediment There are three basic ways to calibrate an OBS sensor with sediment. These are described in the following sections. -
Page 38: Wet-Sediment Calibration
Add three liters of tap water to the suspender tub with the volumetric flash. After measuring the clear-water signal (Step 1, Section 8.6.1, Turbidity ), mount the OBS501 so that the sensor end is 50 mm above the (p. 24) bottom of the suspender tub and secure it in the position that minimizes reflections from the wall;... -
Page 39: Portable Sediment Suspender (Left) And Obs Beam Orientation In
Procedure Record and log the clean-water signal as in Step 1, Section 8.6.1, Turbidity ; see FIGURE 8-3, Position of OBS501 in clean tap water in big black (p.24) . Use the same value, such as, sidescatter, backscatter, or ratio (p. -
Page 40: Operation In High Sediment Loads And Sandy Sediments
NOTE sediment loads. Run the OBS501 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 saves power. The interval can be adjusted over time. -
Page 41: Remove The Screw
® OBS501 Smart Turbidity Meter with ClearSensor Technology Insert a slot screw driver (2.5 mm (0.1 in.) wide blade) into the access port (FIGURE 8-7). Engage the end of the drive shaft and then rotate clockwise until the shutter is free (FIGURE and FIGURE 8-8). -
Page 42: Maintenance
Other solid biocides can be placed in the chamber. To be effective over time, the biocide should be slow to dissolve. The OBS501 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). -
Page 43: Troubleshooting
This will void the warranty and could cause a leak. Plastic (pn 31570) and copper (pn 31569) sleeves are available for the OBS501 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. -
Page 44: References
® OBS501 Smart Turbidity Meter with ClearSensor Technology ® 8-2, Normalized response of OBS501 to AMCO Clear turbidity , and (p. 24) 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. -
Page 45: Importing Short Cut Code Into Crbasic Editor
Appendix A. Importing Short Cut Code Into CRBasic Editor This tutorial shows: • How to import a Short Cut program into a program editor for additional refinement • How to import a wiring diagram from Short Cut into the comments of a custom program Short Cut creates files, which can be imported into CRBasic Editor. - Page 46 Appendix A. Importing Short Cut Code Into CRBasic Editor This character instructs the datalogger compiler to ignore the line when compiling.
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Page 47: Example Programs
'Main Scan Scan(5,Sec,1,0) 'Default Datalogger Battery Voltage measurement 'BattV' Battery(BattV) 'Default Wiring Panel Temperature measurement 'PTemp_C' PanelTemp(PTemp_C,60) 'OBS501 Smart Turbidity Meter (SDI-12) measurements 'Turb_BS', 'Turb_SS', 'Temp_C', and 'WD_OBS' SDI12Recorder(OBS501(),C1,"0","M!",1,0) 'Call Data Tables and Store Data CallTable Table1 CallTable Table2 NextScan... -
Page 48: Cr1000 Sdi-12 Program
Appendix B. Example Programs B.2 CR1000 SDI-12 Program CRBasic Example B-2. CR1000 SDI-12 Program '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) -
Page 49: Cr1000 Rs-232 Program
Scan (30,Sec,0,0) OutString2 = CHR (13) 'a series of carriage returns will put OBS501 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) -
Page 50: Cr1000 Analog Program
Appendix B. Example Programs B.4 CR1000 Analog Program Although this is a CR1000 program, other CRBasic dataloggers are programmed similarly. CRBasic Example B-4. CR1000 Analog Program 'CR1000 Series Datalogger 'OBS501_analog_O&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... -
Page 51: Examples For High Sediment Loads
'CR1000 Series Datalogger 'OBS501 normally open 'In normally open mode the OBS501 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. -
Page 52: Cycle Shutter/Wiper For Each Measurement Cr1000 Program
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. CRBasic Example B-6. Cycle Shutter/Wiper for Each Measurement CR1000 Program 'CR1000 Series Datalogger 'OBS501 cycle shutter each measurement 'Declare Public Variables Public OBS501(4) -
Page 53: Sleeve Installation
Ensure that the 4-40 x ¼ SS Slot Head Screw is fully tightened into the OBS501. Slide the copper (shown) or plastic sleeve over the OBS501 and line up the hole in the sleeve with the screw. Loosen the 4-40 x ¼ SS Slot Head Screw so that it secures the sleeve to... -
Page 55: Sdi-12 Sensor Support
An active sensor responds to each command. Responses have several standard forms and terminate with <CR><LF> (carriage return – line feed). Standard SDI-12 commands supported by the OBS501 are listed in TABLE D-1. TABLE D-1. OBS501 SDI-12 Command and Response Set... -
Page 56: Start Measurement Commands (Am
LoggerNet. The following examples show how to use LoggerNet software to enter transparent mode and change the SDI-12 address of an OBS501 sensor. The same steps are used to enter transparent mode with PC200W and PC400 software after accessing the terminal emulator as previously described. -
Page 57: Cr1000 Datalogger Example
SDI12 <enter>. The response SDI12> indicates that the OBS501 is ready to accept SDI-12 commands. To query the OBS501 for its current SDI-12 address, key in ?! <enter> and the OBS501 will respond with its SDI-12 address. If no characters are typed within 60 seconds, the mode is exited. -
Page 58: Cr1000 Example Of Using The Sdi-12 Transparent Mode To
To change the SDI-12 address, key in aAb! <enter>, where a is the current address from the above step and b is the new address (see FIGURE D-2). The OBS501 will change its address and the datalogger will respond with the new address. To exit SDI-12 transparent mode, select the Close Terminal button. -
Page 59: Factors That Affect Turbidity And Suspended-Sediment Measurements
Appendix E. Factors that Affect Turbidity and Suspended-Sediment Measurements This appendix summarizes 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. -
Page 60: Suspensions With Mud And Sand
Appendix E. Factors that Affect Turbidity and Suspended-Sediment Measurements FIGURE shows the difference in apparent turbidity that can result from different ways of disaggregating sediment. Sonic Probe (Most Aggressive) Sonic Bath Hand Shaking (Least Aggressive) FIGURE E-2. The apparent change in turbidity resulting from disaggregation methods E.2 Suspensions with Mud and Sand As mentioned in Appendix E.1, Particle Size... -
Page 61: High Sediment Concentrations
Appendix D. SDI-12 Sensor Support It is also essential that particle shape remains constant during the monitoring period. OBS-3+ Plates Cubes Spheres 0.01 Scatt ering Angle FIGURE E-3. Relative scattering intensities of grain shapes E.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. -
Page 62: Ir Reflectivity-Sediment Color
Appendix E. Factors that Affect Turbidity and Suspended-Sediment Measurements FIGURE E-4. Response of an OBS sensor to a wide range of SSC E.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. -
Page 63: Water Color
Appendix D. SDI-12 Sensor Support FIGURE E-5. Infrared reflectivity of minerals as a function of 10-Munzell Value E.6 Water Color Some OBS users have been concerned that color from dissolved substances in water samples, not colored particles as discussed in Appendix E.5, IR Reflectivity—Sediment Color , produces erroneously low turbidity (p. - Page 64 Appendix E. Factors that Affect Turbidity and Suspended-Sediment Measurements 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.
- Page 66 Santo Domingo, Heredia 40305 SOUTH AFRICA COSTA RICA • cleroux@csafrica.co.za • info@campbellsci.cc www.campbellsci.co.za www.campbellsci.cc Campbell Scientific Southeast Asia Co., Ltd. Campbell Scientific Ltd. 877/22 Nirvana@Work, Rama 9 Road Campbell Park Suan Luang Subdistrict, Suan Luang District 80 Hathern Road Bangkok 10250...
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