Related Manuals for Campbell OBS500
Summary of Contents for Campbell OBS500
- Page 1 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 ,...
- 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
Table of 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 ..............1 2. Precautions ..............1 3. Initial Inspection ............2 Ships With .................... - Page 8 Examples for High Sediment Loads ..........B-4 B.4.1 Normally Open CR1000 Example ........... B-4 B.4.2 Cycle Shutter/Wiper for Each Measurement CR1000 Program B-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.
- Page 9 Table of Contents 7-6. Position of OBS500 in clean tap water in big black tub..... 25 7-7. OBS500 in 500-TU AMCO Clear ® turbidity standard in 100-mm black polyethylene calibration cup ..........26 7-8. Portable Sediment Suspender (left) and OBS beam orientation in suspender tub (right) ...............
- Page 10 Table of Contents...
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Page 11: Introduction
• 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. -
Page 12: Initial Inspection
(p. 29) • 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 •... -
Page 13: Use Strain Relief To Keep Stress Off The Cable And Provide Extra Security
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°. -
Page 14: Apply Tape To Protect Sensor
OBS500 Smart Turbidity Meter with ClearSensor Technology ® FIGURE 4-2. Apply tape to protect sensor FIGURE 4-3. Secure with hose clamps. Do not overtighten. -
Page 15: Place And Secure Mounting Fixture
OBS500 Smart Turbidity Meter with ClearSensor Technology ® FIGURE 4-4. Place and secure mounting fixture... -
Page 16: Datalogger Programming And Wiring
ResourceDVD. It is included in installations of LoggerNet, PC200W, PC400, or RTDAQ. The following procedure shows using Short Cut to program the OBS500. Open Short Cut and select New Program. Select Datalogger Model and Scan Interval (default of 5 seconds is OK... - Page 17 ® 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 18: Overview
Overview 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. -
Page 19: Turbidity Units
OBS500 Smart Turbidity Meter with ClearSensor Technology ® 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 neighboring light-scattering measurements made on calibration standards such as Formazin, StablCal, or SDVB beads. -
Page 20: Measurement Details
The measurement cycle is activated by commands via SDI-12, RS-232 terminal commands, or a control line(s) going high (analog 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 analog. -
Page 21: Specifications
® 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 μW of optical power. The detectors are low- drift silicon photodiodes with enhanced NIR responsivity. -
Page 22: Installation
Cut does this work for you. See Section 4, QuickStart , for a Short Cut (p. 2) 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. -
Page 23: 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. -
Page 24: Terminal Mode Using 1 And H Commands
Select the correct PC Serial Port and then click Connect (see FIGURE 7-1). The Terminal tab can be used to verify the setup of the OBS500. Select the Terminal tab. Click in the Terminal window and push the Enter key several times. -
Page 25: Settings Editor Screen
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: Datalogger/Rtu Connection
The SDI-12 address is not used while in analog mode. Datalogger/RTU Connection The OBS500 field cable is typically used to connect to a datalogger or RTU. The field cable is a molded-cable assembly that terminates with an MCIL wet pluggable underwater terminator. TABLE shows the contact numbers for the MCIL/MCBH-8 connectors and the electrical functions and wire colors. -
Page 27: Sdi-12 Wiring
OBS500 Smart Turbidity Meter with ClearSensor Technology ® 7.3.1 SDI-12 Wiring TABLE 7-4. 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 28: Analog 0 To 5 Volt Wiring
If you have OS version 1, see Appendix D, SDI-12 and RS-232 NOTE . Use the aI! SDI- Measurement Commands for OS Version 1 (p. D-1) 12 command or use DevConfig to see the OS version downloaded to your OBS500. The OS version can be updated by using DevConfig. -
Page 29: Sdi-12 And Rs-232 Measurement Commands For Os Version
OBS500 Smart Turbidity Meter with ClearSensor Technology ® TABLE 7-7. SDI-12 and RS-232 Measurement Commands for OS Version 2 or Higher Commands Process Values Returned Open Wiper obs (tu) Measure ss (tu) Close temperature (ºC) a = address Send Data... -
Page 30: Sdi-12 Addresses
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. -
Page 31: Terminal Emulator
Only one sensor of the same address can be connected when using the change address command. 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... -
Page 32: 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. If a 9-point calibration is needed, the OBS500 should be sent to Campbell Scientific to perform the calibration. -
Page 33: Normalized Response Of Obs500 To Amco Clear Turbidity. The Inset Shows The Response Function Of A Turbidity Sensor To High-Sediment Concentrations
SSC (mg/l) 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. - Page 34 150 (6) +0.60 +1.20 +4.80 +9.70 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 Swab sensor with an alcohol-soaked towel to sterilize it.
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Page 35: Position Of Obs500 In Clean Tap Water In Big Black Tub
OBS500 Smart Turbidity Meter with ClearSensor Technology ® FIGURE 7-6. Position of OBS500 in clean tap water in big black tub Pour the first SDVB standard into the appropriately sized cup (see TABLE 7-9). Position the OBS sensor in the cup as shown in FIGURE and record 10-second averages of the low- and high-range outputs. -
Page 36: Sediment
OBS500 Smart Turbidity Meter with ClearSensor Technology ® FIGURE 7-7. OBS500 in 500-TU AMCO Clear ® turbidity standard in 100-mm black polyethylene calibration cup 7.5.2 Sediment There are three basic ways to calibrate an OBS sensor with sediment. These are described in the following sections. -
Page 37: In Situ Calibration
Add three liters of tap water to the suspender tub with the volumetric flash. After measuring the clear-water signal (Step 1, Section 7.5.1, Turbidity ), mount the OBS500 so that the sensor end is 50 mm above the (p. 22) bottom of the suspender tub and secure it in the position that minimizes reflections from the wall;... -
Page 38: Programming
(p. 22) 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. -
Page 39: Sdi-12 Programming
Edlog dataloggers are provided at www.campbellsci.com/old-manuals. 7.6.1 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. -
Page 40: Wiper Removal Procedure
OBS500 Smart Turbidity Meter with ClearSensor Technology ® 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. -
Page 41: Remove The Screw
OBS500 Smart Turbidity Meter with ClearSensor Technology ® Remove 4-40 flat head screw Copper plate FIGURE 7-9. Remove the screw Drive shaft access port FIGURE 7-10. Insert screwdriver and rotate clockwise FIGURE 7-11. Shutter disassembled... -
Page 42: Factors That Affect Turbidity And Suspended-Sediment Measurements
OBS500 Smart Turbidity Meter with ClearSensor Technology ® Shutter Floating nut copper plate spacer Floating FIGURE 7-12. Shutter components Factors that Affect Turbidity and Suspended- Sediment Measurements This section summarizes some of the factors that affect OBS measurements and shows how ignoring them can lead to erroneous data. If you are certain that... -
Page 43: Normalized Sensitivity As A Function Of Grain Diameter
OBS500 Smart Turbidity Meter with ClearSensor Technology ® 1.00 0.10 S ~ 1/D 50 0.01 10.0 100.0 1000.0 Median Particle Size (D FIGURE 8-1. Normalized sensitivity as a function of grain diameter Sonic Probe (Most Aggressive) Sonic Bath Hand Shaking (Least Aggressive) FIGURE 8-2. -
Page 44: Suspensions With Mud And Sand
OBS500 Smart Turbidity Meter with ClearSensor Technology ® Suspensions with Mud and Sand As mentioned in Section 8.1, Particle Size , light scattering from particles (p. 32) 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. -
Page 45: High Sediment Concentrations
OBS500 Smart Turbidity Meter with ClearSensor Technology ® 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 46: Water Color
OBS500 Smart Turbidity Meter with ClearSensor Technology ® FIGURE 8-5. Infrared reflectivity of minerals as a function of 10-Munzell Value Water Color Some OBS users have been concerned that color from dissolved substances in water samples, not colored particles as discussed in Section 8.5, IR Reflectivity—Sediment Color... -
Page 47: Maintenance
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). -
Page 48: Troubleshooting
OBS500 Smart Turbidity Meter with ClearSensor Technology ® FIGURE 9-1. DevConfig, Send OS 10. Troubleshooting 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. -
Page 49: Troubleshooting Chart
OBS500 Smart Turbidity Meter with ClearSensor Technology ® The following three tests are used to diagnose malfunctions of an OBS500. 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 ). -
Page 50: References
OBS500 Smart Turbidity Meter with ClearSensor Technology ® 11. References 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.”... -
Page 51: 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 52 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 53: Example Programs
Appendix B. Example Programs B.1 CR1000 SDI-12 Program Although this is a CR1000 program, other CRBasic dataloggers are programmed similarly. CRBasic Example B-1. 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... -
Page 54: Cr1000 Rs-232 Program
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) -
Page 55: Cr1000 Analog Program
Appendix B. Example Programs B.3 CR1000 Analog Program Although this is a CR1000 program, other CRBasic dataloggers are programmed similarly. CRBasic Example B-3. CR1000 Analog Program 'CR1000 Series Datalogger 'OBS500_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 56: Examples For High Sediment Loads
'CR1000 Series Datalogger 'OBS500 normally open 'In normally open mode the OBS500 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 57: 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-5. Cycle Shutter/Wiper for Each Measurement CR1000 Program 'CR1000 Series Datalogger 'OBS500 cycle shutter each measurement 'Declare Public Variables Public OBS500(4) - Page 58 Appendix B. Example Programs...
- Page 59 Appendix C. OBS500 Copper Sleeve Kit Installation Remove the Button Head Hex Screw as shown. Slide the Copper Sleeve over the OBS500 and snap it into place. Install the 4-40 x ¼ SS Slot Head Screw.
- Page 60 Appendix C. OBS500 Copper Sleeve Kit Installation...
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Page 61: Sdi-12 And Rs-232 Measurement Commands
OS version 1. Use the aI! 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... - Page 62 Appendix D. SDI-12 and RS-232 Measurement Commands for OS Version 1 TABLE D-1. SDI-12 and RS-232 Measurement Commands Commands Process Values Returned aM6! Measure obs (tu) aC6! Send Data ss (tu ) ratio (tu) temperature (degc) raw obs (volts) raw ss (volts) open current (ma) close current (ma) wet dry (0=dry 1=wet)
- Page 64 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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