Manual
Contents
1. Figure 2 Installing the Sensor Cap 1 Cap Seal Place the narrow 3 Sensor cap 5 Narrow shoulder is inside the cap shoulder towards probe tip 2 O ring in place on probe tip 4 Screw sensor cap onto probe tip Hach LDO Sensor Calibration Dissolved oxygen concentration is associated with either a concentration in mg L or a percent saturation relative to 100 water saturated air or air saturated water There are three standard methods for calibrating the Hach LDO sensor Each method requires a single point calibration for measurement of concentration in mg L In order to calibrate the sensor for percent saturation reading the local barometric pressure must be determined independently by the user and input into the software during calibration In order to retain calibration accuracy between multiple deployments store with sensor fully immersed in water at all times or at a minimum stored in a sealed container with water saturated air such as a sealed storage cup Make sure the storage cap has at least 10cc of water and is sealed to prevent evaporation It is important that the end of the sensor cap and the sonde temperature sensor are at the same temperature during calibration When calibrating in water saturated air the temperature sensor should be in air When calibrating in air saturated water or water with a known oxygen concentration the temperature sensor should be immersed in water Method 1 Use this method when air satura2. the well mixed water bath Continuous use of compressed air can lead to super saturation of oxygen in the water bath To minimize this effect it is recommended to turn off the air purge prior to final calibration 5 A recommended method for producing air saturated water in the field and using it to calibrate the sensor is as follows a Take a 1 liter bottle and fill 50 with water Another possibility is a 4 liter 1 gallon bottle with 500cc of water Use water that has been at equilibrium with atmospheric pressure for at least 12 hours i e unseal open any bottled water or draw water from a tap well in advance of calibration b Make sure the water in the bottle is close to temperature equilibrium with the calibration environment c Seal the bottle and shake it very vigorously for 40 seconds d With the sonde positioned with sensors facing upright pour the water into the calibration cup fully submersing the Hach LDO sensor cap and the temperature sensor Figure 3 Make sure the water comes close to the top of the calibration cup Place the calibration cup cap upside down Concave upward on top of the calibration cup to cover the calibration cup This stops the exchange of air and allows the local environment to equilibrate Do not tightly seal or otherwise raise the barometric pressure in the calibration cup Make sure that the calibration cup is not in direct sunlight or in the presence of a heat or light source that could change
3. 10 Enter the barometric pressure in the field provided 11 Click CALIBRATE A Calibrate Successful screen will be displayed Figure 4 Method 2 Calibration 1 Calibration Cup 3 Proper Sonde Insertion 2 Filling the Calibration Cup 4 Calibration Cup screwed onto the Sonde Method 3 Use this method when a known calibration standard is applied to the sensor 1 Connect the sensor to a PC 2 Start Hydras 3 LT Wait for Hydras 3 LT to establish communications with the sensor Click the OPERATE SONDE button 3 Click the Calibration tab and select the LDO mg l tab 4 Place the sensor into a solution with a known concentration of oxygen For example a reference tank with a calibrated Hach Luminescent Dissolved Oxygen sensor Make sure that no bubbles are present on the face of the sensor and that the temperature probe is fully immersed 5 Determine the barometric pressure for entry as the calibration standard 6 After the temperature and luminescent dissolved oxygen readings have stabilized wait an additional 3 5 minutes to assure that the luminescent dissolved oxygen sensor material has reached the same temperature as the water bath Enter the barometric pressure in the field provided 7 Determine dissolved oxygen in mg L in the sample using a known reference 8 Enter the known concentration of oxygen the Dissolved Oxygen mg L field oo Ey HYDROLAB COM 2 SB ioii SpCond mS cm SpCond p5 cm Re
4. HYDROLAB 00745589 Instruction Sheet Hach LDO Sensor Safety Precautions Introduction Please read this entire instruction sheet before operating this sensor Pay particular attention to all danger and caution statements Failure to do so could result in serious injury to the operator or damage to the sensor Do not use or install this sensor in any manner other than that which is specified in this instruction sheet Use of Hazard Information If multiple hazards exist this instruction sheet will use the signal word Danger Caution Note corresponding to the greatest hazard DANGER Indicates a potentially or imminently hazardous situation which if not avoided could result in death or serious injury CAUTION Indicates a potentially hazardous situation that may result in minor or moderate injury or instrument damage Important Note Information that requires special emphasis Note Information that supplements points in the main text Precautionary Labels Read all labels and tags attached to the instrument Personal injury or damage to the instrument could occur if not observed This symbol if noted on the instrument references the instruction sheet for operational and or safety information Electrical equipment marked with this symbol may not be disposed of in European public disposal systems after 12 August of 2005 In conformity with European local and national regulations EU Directive 2002 96 EC Europea
5. J Hy DROLAB COM 1 System Online Monitoring Log Files Parameter Setup Calibration Settings Sotware Log File Type Status Created Size Bytes S cans Start Logging Stop Logging Logging Interval Sensor Warmup Circulator warmup Parameters in Sonde SpCond rmn5 crn SpCond p5 7cm Res k 0 cm Sal ppt TOS gl Depth 0 meters Depth vs volts Depth Vy malta LOO Sat i rF mI 11 36 39 AM re Specifications Log File l Save Settings Time Triggered Disabled 02 23 20 until start 3172005 00 00 00 0r 497250 Bytes left 2 12005 mhemm s 12005 Shemo 00 15 00 00 00 30 00 00 30 gt F Audio i Parameters in Log File Temp C pH Units SpCond rm5 cr Depth 0 meters LOO Sat LOO mgl Internal B attery Volts Specifications are subject to change without notice Sensor is covered by a two year warranty Sensor cap is covered by a one year warranty For Technical Assistance Price Information and Ordering Hach Environmental In the U S A Call toll free 800 949 3766 P O Box 389 E hnvir onmental Outside the U S A Contact the Hach Environmental office Loveland CO 80539 0389 Be Right The Environment is Worth it or distributor serving you Telephone 970 669 3050 On the Worldwide Web www hachenvironmental com FAX 970 461 3921 Hach Company 2006 All
6. n electrical equipment users must now return old or end of life equipment to the Producer for disposal at no charge to the user Note For return for recycling please contact the equipment producer or supplier for instructions on how to return end of life equipment producer supplied electrical accessories and all auxiliary items for proper disposal The luminescent dissolved oxygen Hach LDO Figure 1 sensor is an in situ optical probe that determines the dissolved oxygen concentration in a given water sample The sensor cap is coated with a luminescent material Blue light from a LED is transmitted to the sensor surface The blue light excites the luminescent material As the luminescent material relaxes it emits red light The time from when the blue light was sent and the red light is emitted is measured The more oxygen that is present the shorter the time it takes for the red light to be emitted This time is measured and correlated to the oxygen concentration Between the flashes of blue light a red LED is flashed on the sensor and used as an internal reference to help validate each measurement The sonde can display the oxygen either as a concentration from 0 20 mg L or as a percent saturation with either air saturated water or water saturated air serving as the 100 reference point Figure 1 Hach LDO Sensor Maintenance Important Note Do not use organic solvent solutions such as acetone or methanol with the Hach LDO sensor These
7. provided 8 Click CALIBRATE A Calibrate Successful screen will be displayed Method 2 Use this method when water saturated air is applied to the sensor 1 Connect the sensor to a PC 2 Start Hydras 3 LT Wait for Hydras 3 LT to establish communications with the sensor Click the OPERATE SONDE button 3 Click the Calibration tab and select the LDO SAT tab 4 Place the calibration cup with one end sealed so that the calibration cup opening is facing upwards The sonde will be inserted downwards into this cup item 1 Figure 4 5 Fill the calibration cup with approximately 2 inches of deionized water or tap water specific conductance less than 0 5 mS cm item 2 Figure 4 Water will not touch the top of the sensor cap 6 Carefully remove any water droplets from the sensor cap and temperature probe with the corner of a tissue or clean cotton cloth It is important that no evaporative cooling take place either on the sensor cap or the temperature probe during calibration Note It is important to maintain temperature stability during calibration Care should be taken to keep the sonde out of direct sunlight or away from any other energy heat source which will cause the temperature in the calibration cup to change during calibration A reflective sun shield is recommended if no natural shade is available If the temperature in the calibration cup changes more than 0 5 C during the calibration it is recommended to recalibrate
8. rights reserved Printed in U S A eac kt te dk February 2006 Edition 4
9. s kO cm Sal ppt TDS g l pH Units ORP mv Depl00 meters DeplO0 feet Depl00 psia LOO SAT LDO mal LDO_BP mmHg Turbidity Rev Turbidity NTU e Curent Value 0 00 mgl 11 11 2004 4 18 43 PM Temp 75 0 F LOO_BP mmHg fail Enter BP mmHg LDO mgl 0 00 Enter QDO mgl Calibrate Reset 4 16 45 PM Zz 9 Click CALIBRATE A Calibrate Successful screen will be displayed Battery Life Optimization Notes The luminescent dissolved oxygen Hach LDO sensor is a non consumptive oxygen sensor It does not require a circulator for operation in still or low flowing water The warm up time for the Hach LDO sensor should be set to 30 seconds to optimize battery life The default warm up time setting in the sonde is 2 minutes originally intended to accommodate the warm up time of the polarographic dissolved oxygen sensor Clark Cell Two minutes allowed the Clark Cell to stabilize and the circulator to achieve a constant flow across the membrane The Hach LDO sensor does not require the 2 minute warm up time Using the 2 minute warm up time with the Hach LDO sensor will significantly decrease the deployment time for battery operated instruments To optimize the battery life the manufacturer recommends setting both the sensor and circulator warm up time to 30 seconds For systems without circulators it is still necessary to enter the 30 second circulator warm up time E
10. solvents will damage the plastic sensor cap The Hach LDO sensor is not affected by fouling or other debris unless the growth is an organism that locally consumes or produces oxygen such as barnacles or algae growing on the sensor cap Nevertheless the manufacturer recommends periodic maintenance to remove contaminants such as oil biological growth dirt etc Sensor maintenance should be conducted after every deployment cycle 1 Flush the entire instrument with clean fresh water Use soapy water and a soft brush to clean the outside surfaces of the instrument 2 Soak the entire instrument in fresh water for at least 30 minutes 3 Visually inspect the sensor cap Use optical tissue or a cotton swab with soapy water to clean the sensor cap Rinse with fresh water It is not advised to remove the sensor cap unless the cap is being replaced If the cap is sealed properly using the top O ring seal no water should be present between the sensor cap and the clear plastic window at the top of the probe If water is present between the sensor cap and the clear plastic window at the top of the probe remove the cap and thoroughly dry the inside of the cap and the clear plastic window The cap may require replacement Installing the Sensor Cap 1 Place the cap seal item 1 Figure 2 and the O ring item 2 Figure 2 on the probe 2 Screw on the sensor cap Figure 2 so that the o ring seal is compressed Do not over tighten the sensor cap
11. ted water is applied to the sensor 1 Connect the sensor to a PC 2 Start Hydras 3 LT Wait for Hydras 3 LT to establish communications with the sensor Click the OPERATE SONDE button 3 Click the Calibration tab and select the LDO SAT tab Note It is important to maintain temperature stability during calibration Care should be taken to keep the sonde out of direct sunlight or away from any other energy heat source which will cause the temperature in the calibration cup to change during calibration A reflective sun shield is recommended if no natural shade is available If the temperature in the calibration cup changes more than 0 5 C during the calibration it is recommended to recalibrate the sensor zE iol x SpCond mS cm SpCond p5 cm Res k0 cm Sal ppt TOS gl pH Units LDO mg LDO_BP mmHg Turbidity Rev Turbidity NTU ORP mv Dep100 meters Dep100 feet Dep100 psia LDO SAT Curent Value 0 0 SAT 11 11 2004 4 19 23 PM Temp 75 1 F LOO_BP mmHg fail Enter BP mmHg Calibrate Reset 4 19 25 PM 4 Calibrate the sensor using temperature stabilized air saturated water In a laboratory environment this is typically done by allowing water to equilibrate at least 12 hours after being run from a faucet or decanted from an opened water bottle The water is air saturated in a temperature stabilized container using an air stone injecting air into
12. the temperature in the calibration cup If needed protect the calibration cup with a reflective shield Figure 3 Method 1 Calibration 1 Calibration cup filled with temperature stabilized air saturated water 2 Proper coverage using inverted cap 6 Determine the barometric pressure for entry as the calibration standard The barometric pressure needs to be in mmHg 1mmHg 0 00133322 bar 133 322 pascal 0 019336778 pounds square inch absolute Local Barometric Pressure BP in mmHG can be estimated using BP 780 2 5 A 100 or BP 780 2 5 A 30 5 where BP Barometric pressure at altitude BP Barometric pressure at sea level Ag Altitude in feet Am ALtitude in meters If using the local weather bureau BP remember these numbers are corrected to sea level To calculate the uncorrected atmospheric pressure BP use the following equations BP BP 2 5 A 100 or BP BP 2 5 A 30 5 where BP Barometric pressure at altitude BP Barometric pressure at sea level Ag Altitude in feet Am ALtitude in meters Local barometric pressure in mbar BPmbar can be converted to local barometric pressure in mmMG BPmmHG using BPmmHG 0 75 x BPmbar 7 In either laboratory or field prepared air saturated water wait 3 5 minutes to assure that the luminescent dissolved oxygen sensor material has reached the same temperature as the water bath Enter the barometric pressure in the field
13. the sensor T 8 Gently set the sonde with sensors down into the calibration cup blocking any air exchange with the outside environment Do not screw the calibration cup fully onto the sonde body as the compression of the o ring will increase the pressure inside the calibration cup to above the barometric pressure and give a false 100 saturated reading The goal is to block air exchange between the sealed calibration cup and the outside items 3 and 4 Figure 4 Allow the dissolved oxygen and temperature readings to stabilize As the temperature sensor has a smaller thermal mass than the luminescent dissolved oxygen sensor it is best to allow the entire unit to stabilize for an additional 3 5 minutes after the temperature sensor stabilizes At this point Fe HYDROLAB COM 2 System Online Monitoring Log Files Parameter Setup Calibration Settings Software SpCond mS cm SpCond pS cm Res kO cm Sal ppt TDS al pH Units LDO ma LOOLBP mmHo Turbidity Rev Turbidity NTU ORF m Dep100 meters Dep100 feet Dep100 psia LDO SAT Current Yalue 0 0 SAT 11 11 2004 4 19 23 PM Temp 75 1 F LOO_BP mmHg r60 Enter BP mmHg Calibrate Reset 4 19 25 PM the air inside the calibration cup should be fully saturated with water hence the name water saturated air 9 Determine the barometric pressure for entry as the calibration standard
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