Campbell OBS-3A Manuel Page 1

OBS-3A Turbidity and Temperature Monitoring SystemRevision: 7/13Copyright © 2007-2013Campbell Scientific, Inc.

OBS-3A Turbidity and Temperature Monitoring System 3.1 Ships With CSI pn 21229 Accessory Kit ResourceDVD CSI pn 29225 HydroSci Software on DVD 4. Ov

OBS-3A Turbidity and Temperature Monitoring System FIGURE 4-1. Anatomy of an OBS sensor 4.2 Temperature and Optional Sensors Temperature is measure

OBS-3A Turbidity and Temperature Monitoring System Light transmission in water is attenuated by scattering (deflection by water molecules, and suspend

OBS-3A Turbidity and Temperature Monitoring System 5.1 Measurement Range Turbidity (AMCO Clear): 0.4 to 4,000 NTU1 Mud (D50=20 µm): 0.4 to 5,000 mg/

OBS-3A Turbidity and Temperature Monitoring System Battery capacity: 18 A h Maximum battery life: 8,000 hours Data protocols: RS-232 / RS-485 Maximu

OBS-3A Turbidity and Temperature Monitoring System TABLE 6-1. Working and Maximum Depths Pressure Sensor Working Depth Maximum Depth 0.2 Bar 0 to

OBS-3A Turbidity and Temperature Monitoring System the cable grip and connector and put chafe protection on the sensor head where it contacts the wire

OBS-3A Turbidity and Temperature Monitoring System FIGURE 6-2. Battery installation For extended deployment time, lithium batteries are a good alter

OBS-3A Turbidity and Temperature Monitoring System 6.3 Running HydroSci 1. Select the HydroSci program to start the program. 2. Physically connect

OBS-3A Turbidity and Temperature Monitoring System 3. Select OBS-3A on the lift side of the screen and select the appropriate COM Port and Baud Rate

OBS-3A Turbidity and Temperature Monitoring System 7. After you have finished interacting with your sensor, click on the Connection tab and press the

OBS-3A Turbidity and Temperature Monitoring System Blow on the temperature sensor to observe an increase in temperature (red trace line on the top plo

OBS-3A Turbidity and Temperature Monitoring System Show Terminal tab brings up a terminal screen that allows you to view the commands being sent to th

OBS-3A Turbidity and Temperature Monitoring System 6.8.2 Operations Put OBS-3A to Sleep Press the Sleep button to put the OBS-3A in low-power, slee

OBS-3A Turbidity and Temperature Monitoring System HydroSci will confirm if you want to put the OBS-3A to sleep. Clear OBS-3A Data Storage Press the

OBS-3A Turbidity and Temperature Monitoring System Barometric Correction The OBS-3A measures absolute pressure so a correction must be made for barome

OBS-3A Turbidity and Temperature Monitoring System Change to RS-232 To switch from RS-485 communication to RS-232 communication, press the RS-232 butt

OBS-3A Turbidity and Temperature Monitoring System If it becomes necessary to load coefficients from a saved file, press the Load Coefficients from Fi

OBS-3A Turbidity and Temperature Monitoring System Calibration The Calibration box can be used to calibrate the OBS-3A for NTU or mg/L measurements.

OBS-3A Turbidity and Temperature Monitoring System You will be asked whether or not you want to log data to a file on your computer. In survey mod

Warranty “PRODUCTS MANUFACTURED BY CAMPBELL SCIENTIFIC, INC. are warranted by Campbell Scientific, Inc. (“Campbell”) to be free from defects in materi

OBS-3A Turbidity and Temperature Monitoring System You can press the Load Configuration From File button to load a configuration that has previously

OBS-3A Turbidity and Temperature Monitoring System Units of Measure Select the units for depth (Meters or Feet). Sensor Measurements Select the check

OBS-3A Turbidity and Temperature Monitoring System You will be asked whether or not you want to log data to a file on your computer. After setting

OBS-3A Turbidity and Temperature Monitoring System • Wave Setup Wave Setup fields are only enabled when Depth is selected under Sensor Measurements a

OBS-3A Turbidity and Temperature Monitoring System o Rate Rate is the frequency of sampling for the duration of measurements. All sensors are samp

OBS-3A Turbidity and Temperature Monitoring System Go to the Connection tab and press Disconnect to disconnect from the OBS-3A. Unplug the test cabl

OBS-3A Turbidity and Temperature Monitoring System • Water Density Specify the water temperature and salinity. The specified temperature and salini

OBS-3A Turbidity and Temperature Monitoring System • Sample Settings o Duration This is the length of time in seconds that the OBS-3A is measuring

OBS-3A Turbidity and Temperature Monitoring System 6.8.6 Setpoint Configuration Setpoint Configuration mode is used for fast sampling of events such

OBS-3A Turbidity and Temperature Monitoring System • Sensor Measurements Select the check boxes next to the sensor measurements you wish to make. F

Assistance Products may not be returned without prior authorization. The following contact information is for US and international customers residing

OBS-3A Turbidity and Temperature Monitoring System • Interval Settings o Slow Interval The time, in seconds, between the start of one sample and t

OBS-3A Turbidity and Temperature Monitoring System Temperature, Salinity, Concentration, and Depth are shown on the charts. Only the sensor measureme

OBS-3A Turbidity and Temperature Monitoring System All sensor measurements selected in the configuration will be shown in the table view. Use the scr

OBS-3A Turbidity and Temperature Monitoring System 6.10 View Data The View Data screen can be used to view data stored on the OBS-3A from cyclic, sch

OBS-3A Turbidity and Temperature Monitoring System 3. A screen asking if the OBS-3A is currently sampling will appear. If you are ready to stop samp

OBS-3A Turbidity and Temperature Monitoring System 4. Go to View Data to save data in a file. 5. Highlight the data with the start and end times y

OBS-3A Turbidity and Temperature Monitoring System 6. Once the correct data is selected, press Save Data File. The Save As screen will appear, name

OBS-3A Turbidity and Temperature Monitoring System Then press the New Line Graph button and a new screen will appear with various graphing options.

OBS-3A Turbidity and Temperature Monitoring System . The spreadsheet of data can also be printed. 6.11 Show Terminal The Show Terminal tab brings u

OBS-3A Turbidity and Temperature Monitoring System 6.12 Shutdown From the OBS-3A Configuration | Operations tab, select Put OBS-3A To Sleep. It wi

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 spec

OBS-3A Turbidity and Temperature Monitoring System 6.14 Erasing Memory Data To erase the memory data on the OBS-3A, go to OBS-3A Configuration | Op

OBS-3A Turbidity and Temperature Monitoring System 7. Calibration It is a good idea to use the Retrieve and Save Coefficients to File button (under

OBS-3A Turbidity and Temperature Monitoring System • 100 ml to deliver (TD) volumetric pipette • 25 ml TD measuring pipette • 2 gallons filtered di

OBS-3A Turbidity and Temperature Monitoring System 3. Prepare the next NTU standard and put the OBS-3A in it. Repeat steps 1 and 2 for all calibrati

OBS-3A Turbidity and Temperature Monitoring System The formula for preparing turbidity standards other than shown in TABLE 7-1 is: ⎥⎦⎤⎢⎣⎡+=stkdwstkstk

OBS-3A Turbidity and Temperature Monitoring System 7.2.1 Equipment and Materials • Dry, completely disaggregated bottom sediment or suspended matter

OBS-3A Turbidity and Temperature Monitoring System 10 20 30 40 50Sediment Concentration (mg/l)0102030405060Turbidity (NTU)Hand Shaking15-min. Sonic Ba

OBS-3A Turbidity and Temperature Monitoring System Sediment concentrations are calculated with the following equations: mg/lρMVMssis=⎥⎦⎤⎢⎣⎡+ ;

OBS-3A Turbidity and Temperature Monitoring System FIGURE 8-1. Component locations Unit does not communicate with PC. There are several possible c

OBS-3A Turbidity and Temperature Monitoring System b. If the OBS-3A still fails to respond, try changing baud rate speeds by selecting Attempt to f

Table of Contents 6.13 Excel Spreadsheets ... 41 6.14 Erasing Memory Data..

OBS-3A Turbidity and Temperature Monitoring System Power failed due to battery clip corrosion or a broken power wire. Check for a broken red wire conn

OBS-3A Turbidity and Temperature Monitoring System 9. Maintenance 9.1 OBS Sensor The OBS sensor must be kept clean to measure sediment concentration

OBS-3A Turbidity and Temperature Monitoring System during surveys or after each deployment. A sensor that has been stored dry should be soaked in wat

OBS-3A Turbidity and Temperature Monitoring System 9.5 Pressure Housing The pressure housing and O-ring seals require little maintenance unless the h

OBS-3A Turbidity and Temperature Monitoring System 10.1 Particle Size The size of suspended sediment particles typically ranges from about 0.2 to 500

OBS-3A Turbidity and Temperature Monitoring System 10.2 Suspensions with Mud and Sand As mentioned earlier, backscattering from particles is inversel

OBS-3A Turbidity and Temperature Monitoring System 10.3 High Sediment Concentrations At high sediment concentrations, particularly in suspensions of

OBS-3A Turbidity and Temperature Monitoring System 10.4 Sediment Color Sediment color, after particle size, has a major effect on OBS sensitivity, an

OBS-3A Turbidity and Temperature Monitoring System 10.6 Bubbles Although bubbles efficiently scatter IR, monitoring in most natural environments show

OBS-3A Turbidity and Temperature Monitoring System 10.7 Biological and Chemical Fouling Sensor cleaning is essential during extended deployments. In

Table of Contents Tables 6-1. Working and Maximum Depths...7 7-1. Mixing Volumes for Formazi

OBS-3A Turbidity and Temperature Monitoring System 62 Standard Methods for the Examination of Water and Wastewater, 20th Edition. 1998. 2130 Turbidity

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Table of Contents iv

OBS-3A Turbidity and Temperature Monitoring System 1. Introduction The OBS-3A combines our OBS® probe with pressure, temperature, and conductivity s