HOBO U24 Conductivity Logger (U24
Contents
1. in the HOBOware Conductivity Assistant to calibrate the readings for the corresponding data series offloaded from the logger There are three methods for obtaining accurate calibration readings The first method involves placing the meter s probe into the water next to the logger The second method involves placing the logger and meter probe in a field water sample ina jar In both methods the conductivity meter probe must be close to the data logger but not touching so that it is measuring water at the same conductivity as the logger The third method involves taking a sample back to the office to measure with a meter there If the conductivity in the water where the logger is deployed is stable and it is easy to reach the logger then you can obtain calibration readings by placing the probe directly into the water next to the logger However taking calibration readings some locations such as in wells can be difficult because it may be hard to get the meter probe next to the logger In these instances you should fill a jar with a water sample from where the logger is deployed to take the calibration readings To obtain the water sample from a well or stilling well you can use a bailer with a diameter that is small enough to fit down the well Note Some salt residue may remain on the logger from factory calibration Carefully rinse the logger in distilled water or clean freshwater to remove any residual salt before taking your firs2. that segment of the logger s deployment Refer to the Help for the Conductivity Assistant for more details Save your changes to a project file To obtain a three year battery life a logging interval of one minute or greater should be used and the logger should be operated and stored at temperatures between 4 Repeat steps 1 through 3 for all data files 0 and 25 C 32 and 77 F e Battery Voltage The logger can report and log its battery Maintenance voltage If the battery falls below 3 1 V the logger will The logger requires the following periodic maintenance to record a bad battery event in the datafile If the datafile ensure optimal operation contains bad battery events or if logged battery voltage repeatedly falls below 3 3 V the battery is failing and the logger should be returned to Onset for battery replacement Note that the logger does not have to be recording the battery channel for it to detect bad battery events The logger will record these events regardless of what channels are logged e Clean the sensor Mix several drops of dish detergent or biodegradable soap in a cup of tap water with a clean cotton swab Clean the sensor face using the cotton swab and then rinse the sensor with clean or distilled water Do not scratch the sensor face with a sharp tool e Check for biofouling Biofouling and excessive marine growth on the logger will compromise accuracy Organisms that grow on the sensor can i
3. HOBO U24 Conductivity Logger U24 001 Manual MOBO concsscrriry Logger onset Range 0 to 10000 uS cm PR U24 001 SM STOVEDO TEL HOBO Conductivity Logger U24 001 Included Item e Communications window protective cap Required Items e Coupler COUPLER2 C with USB Optic Base Station BASE U 4 or HOBO Waterproof Shuttle U DTW 1 e HOBOware Pro 3 2 or later with the Conductivity Assistant 2 1 or later Accessories e U2X Protective Housing HOUSING U2X e Replacement communications window protective caps U22 U24 CAP 15070 F MAN U24x The HOBO U24 conductivity logger measures actual conductivity and temperature and can provide specific conductance at 25 C with the HOBOware Conductivity Assistant These easily deployable rugged loggers provide the data you need for monitoring water purity and the impact of pollutants in fresh water There is an optional U2X Protective Housing accessory HOUSING U2X available to protect the logger and simplify mounting in harsh environments Specifications Measurements Conductivity Calibrated Measurement Ranges Conductivity Calibrated Range Temperature Range Conductivity Extended Ranges Temperature Measurement Range Specific Conductance Accuracy in Calibrated Range Conductivity Resolution Temperature Accuracy in Calibrated Range Temperature Resolution Conductivity Drift Response Time Operating Range Memory Sample Rate Cloc
4. e field 1 Calibrate the field conductivity meter before using it to take field readings 2 Measure the actual conductivity and temperature values with the field meter using one of the calibration methods on page 4 3 Remove the logger from the water if it hasn t already been removed for the calibration measurement Remove the logger from the protective housing if applicable and remove the protective cap 4 Read out the data from the logger using a shuttle 5 Relaunch the logger 6 Clean the sensor see Maintenance on the next page for more details 7 Place the protective cap back on the logger and remount the logger inside the protective housing if applicable 8 Redeploy the logger in the stream and take another calibration measurement Use HOBOware to calibrate data and convert to specific conductance 1 Offload the most recent data files from the shuttle or loggers to your computer 2 Open a data file in HOBOware www onsetcomp com HOBO U24 Conductivity Logger U24 001 Manual 3 Use the HOBOware Conductivity Assistant to calibrate the the coupler will result in significantly lower battery life readings and adjust for drift caused by fouling You will For example continuous logging at a one second logging need to enter the field meter conductivity and temperature interval will result in a battery life of approximately one readings and times from the beginning and optionally the month end of
5. easily and help with communication 4 Insert the logger into the coupler aligning the bump arrow on the coupler with the arrow on the logger Be sure that it is properly seated in the coupler If the logger has never been connected to the computer before it may take a few seconds for the new hardware to be detected by the computer NOTE If you are using the HOBO Waterproof Shuttle as a base station with a computer briefly press the Coupler Lever to put the shuttle into base station mode You can also align the coupler with the hole on the backside of the sensor Align bump arrow on the coupler with the arrow on the U24 MAR ati Coupler To base station Coupler Lever or shuttle for use with HOBO Waterproof Shuttle WARNING Do not leave the logger in the coupler for extended periods of time When connected to a coupler the logger is awake and consumes significantly more power than when it is disconnected and considered asleep Always remove the logger from the Optic Base Station or HOBO Waterproof Shuttle as soon as possible after launching reading out or checking the status to avoid draining the battery Launching the Logger Before deploying the logger in the field perform the following steps in the office 1 Start HOBOware 2 Connect the logger to the computer as described in the previous section www onsetcomp com 3 Verify the status Click the status button on the toolbar and
6. er activity such as Bad Battery or Host Connected Events help you determine what was happening while the logger was logging Communication To connect the logger to a computer use either the Optic USB Base Station BASE U 4 or HOBO Waterproof Shuttle U DTW 1 with a coupler COUPLER2 C IMPORTANT USB 2 0 specifications do not guarantee operation outside the range of 0 C 32 F to 50 C 122 F To launch and read out the logger in the field use one of these methods e Laptop computer with Optic USB Base Station BASE U 4 and a coupler COUPLER2 C e HOBO Waterproof Shuttle U DTW 1 Firmware Version 3 2 0 or later and a coupler COUPLER2 C 1 800 LOGGERS HOBO U24 Conductivity Logger U24 001 Manual e HOBO U Shuttle U DT 1 Firmware Version 1 14m030 or later with Optic USB Base Station and coupler COUPLER2 C The optical interface allows the logger to be offloaded without breaking the integrity of the seals The USB compatibility allows for easy setup and fast downloads Connecting the Logger to a Computer or Waterproof Shuttle 1 Follow the instructions that came with your base station or Waterproof Shuttle to attach it to a USB port on the computer 2 Attach the coupler to the base station or shuttle 3 Wipe off any residue or slime from the area of the logger that will go into the coupler including the communication window This will help the logger slide in and out of the coupler more
7. erature and actual conductivity of the sample with a meter and write down the values next to the time you noted in step 2 Note If you ve taken the calibration readings in specific conductivity you can convert the readings back to actual conductivity Use the temperature readings from the meter or logger to convert the conductivity reading following the specific conductivity calculation used by your meter consult the meter documentation If the meter uses a standard linear compensation you can use the following formula to convert it This equation calculates the electrical conductivity Ye from a measured water temperature T and from a measured specific conductance at 25 C C using the linear temperature coefficient entered into the meter Y C 1 25 T a 100 Where Y Calculated Electrical Conductivity T water temperature in degrees C measured by the meter C Specific Conductance measured by the meter a linear temperature coefficient degrees C entered into the meter to calculate specific conductance Deploying the Logger The HOBO U24 Conductivity logger is designed to be easy to deploy in many environments The small size of the logger is convenient for use in small wells and allows the logger to be mounted and or hidden in the field Follow these guidelines when deploying the logger e Make sure the logger is located where it will receive a steady flow of the water that is being monitored e W
8. hen deploying the logger in rivers streams and ponds insert the logger in a PVC or ABS pipe if possible The PVC pipe should have enough holes to ensure good circulation of water e To avoid bubbles collecting on the sensor make sure the sensor face is vertical and avoid sudden temperature changes e Do not place any conductive materials or metals within 2 5 cm 1 in of the sensor e Avoid deploying the logger in freezing water with moving ice e Use the included cap to protect the communications window in the logger from fouling and abrasion Place the protective cap over the communications window before deploying the logger e Use the U2X Protective Housing HOUSING U2xX for added protection to the logger in harsh environments To deploy the logger at each site 1 Launch the logger with a laptop or shuttle 2 Take a calibration reading as described on page 4 1 800 LOGGERS HOBO U24 Conductivity Logger U24 001 Manual 3 Deploy the logger in the water if it hasn t already been placed in the water following the guidelines recommended above 4 Repeat steps 1 through 3 for each logger deployed Be sure to take a new calibration reading for each logger that you deploy GROUND LEVE U24 CONDUCTIVITY WATER LEVEL LOGGER Reading Out the Logger and Calibrating Data with HOBOware Your readout and maintenance schedule will be determined by the amount of fouling at the site To read out the logger in th
9. k Accuracy Battery Battery Life Maximum Depth Weight Size Wetted Housing Materials CE Actual Conductivity Temperature Specific Conductance at 25 C calculated Low Range 0 to 1 000 uS cm Full Range O to 10 000 uS cm 5 to 35 C 41 to 95 F Low Range 0 to 2 500 uS cm Full Range O to 15 000 uS cm 2 to 36 C 28 to 97 F Low Range 3 of reading or 5 uS cm and Full Range 3 of reading or 20 uS cm whichever is greater using Conductivity Data Assistant and calibration measurements 1 uS cm 0 1 C 0 2 F 0 01 C 0 02 F Less than 3 sensor drift per year exclusive of drift from fouling 1 second to 90 of change in water 2 to 36 C 28 to 97 F non freezing 18 500 temperature and conductivity measurements when using one conductivity range 14 400 sets of measurements when using both conductivity ranges 64 KB total memory 1 second to 18 hrs fixed or multiple rate sampling with up to 8 user defined sampling intervals 1 minute per month 3 6 Volt lithium battery 3 years at 1 minute logging 70 m 225 ft 193 g 6 82 oz buoyancy in freshwater 59 8 g 2 11 oz 3 18 cm diameter x 16 5 cm with 6 3 mm mounting hole 1 25 in diameter x 6 5 in 0 25 in hole Delrin epoxy stainless steel retaining ring polypropylene Buna rubber O ring titanium pentoxide inert coating over sensor The CE Marking identifies this product as complying with all relevant direc
10. nd keeping the logger connected to 1 800 LOGGERS 564 4377 508 759 9500 2010 2013 Onset Computer Corporation All rights reserved Onset HOBO and HOBOware are www onsetcomp com loggerhelp onsetcomp com trademarks or registered trademarks of Onset Computer Corporation 15070 F MAN U24x
11. nterfere with the sensor s operation and eventually make the sensor unusable If the deployment area is prone to biofouling check the logger periodically for marine growth e Replacing the Battery To have your logger s battery and sensor replaced contact Onset or your place of purchase for return arrangements Do not attempt to replace the battery yourself Severe damage to the logger will result if the case is opened without special tools and the warranty will be voided e Be careful of solvents Check a materials compatibility chart before deploying the logger in locations where A WARNING Do not cut open incinerate heat above 100 C untested solvents are present Refer to the specifications 212 F or recharge the lithium battery The battery may for wetted housing materials on page 1 explode if the logger is exposed to extreme heat or conditions that could damage or destroy the battery case Do not dispose Battery Guidelines of the logger or battery in fire Do not expose the contents of the battery to water Dispose of the battery according to local e Battery Life The battery life of the logger should be regulations for lithium batteries three years or more Actual battery life is a function of the number of deployments logging interval and operation storage temperature of the logger Frequent deployments with logging intervals of less than one minute continuous storage operation at temperatures above 35 C 95 a
12. observe that the temperature is near the actual temperature 4 Launch the logger with the correct range Refer to the specifications on page 1 for both calibrated and extended ranges the calibrated ranges are also printed on the logger housing The logger will not record readings outside of the extended range selected If in doubt on the range needed for your deployment or for environments with wide fluctuations select both ranges This will shorten the deployment duration from 18 500 samples to 14 400 samples per parameter not logging battery voltage See the HOBOware User s Guide or online help for details on launching Note Logging battery voltage is not essential because you can check the battery using the Status screen at launch or readout of the logger Logging the battery voltage will reduce the number of conductivity and temperature readings you can log Taking Calibration Readings It is important to take temperature and conductivity calibration readings with a portable conductivity meter at both the beginning launchtime and end of a deployment readout because these readings are necessary for data calibration and to compensate for any measurement drift during deployment The conductivity calibration readings should be the actual conductivity without temperature compensation not in specific conductance at 25 C and should be recorded in a notebook with the time and location of the reading You will use these readings
13. t calibration readings 1 800 LOGGERS HOBO U24 Conductivity Logger U24 001 Manual Method 1 Taking readings directly in the water recommended for locations with access for the field meter probe and with conductivity that is stable 1 If you have just deployed the logger allow enough time for the logger temperature to stabilize for the best accuracy approximately 15 minutes 2 Gently tap the logger to remove any bubbles from the surface Tug the cable if you cannot reach the logger itself 3 Measure the temperature and actual conductivity with the field meter making sure the meter probe readings stabilize per the meter s specification Record the values time and location of the readings in a field notebook for use later in the HOBOware Conductivity Assistant Method 2 Taking readings in a jar recommended for readings in wells or in water with rapidly changing conductivity such as areas with saltwater and freshwater mixing 1 Take a sample of water in a jar that is large enough to hold both the logger and the probe from a portable conductivity meter leaving an inch of space between the probe and the logger For wells use a bailer to obtain the water sample 2 Leave the logger and the meter probe submerged in this jar of water long enough so they reach temperature equilibrium and the logger has logged at least three readings allow at least 15 minutes for the best accuracy Three readings are necessary beca
14. tives in the European Union EU Protecting the Logger IMPORTANT This logger can be damaged by shock Always handle the logger with care The logger may be damaged if it is dropped Use proper packaging when transporting or shipping the logger Do not attempt to open the logger case or sensor housing Disassembling of the logger case or sensor housing will cause serious damage to the sensor and logger electronics There are no user serviceable parts inside the case Contact Onset Technical Support at 1 800 LOGGERS 1 800 564 4377 or an authorized Onset dealer if your logger requires servicing Logger case Sensor housing i Communications window place the cap at right over the window to protect it during deployment Sensor face Do not scratch the sensor face with a sharp tool Operation An LED in the communications window of the logger confirms logger operation When the logger is logging the LED blinks once every one to four seconds the shorter the logging interval the faster the LED blinks The LED also blinks when the logger is recording a sample When the logger is awaiting a start because it was launched in Start at Interval or Delayed Start mode the LED blinks once every eight seconds until logging begins The logger can record two types of data samples and events Samples are the sensor measurements recorded at each logging interval Events are independent occurrences triggered by a logg
15. use this will help you identify which readings were taken while the logger is in the jar 3 Measure the temperature and actual conductivity with the field meter Record the values time and location of the reading in a field notebook for use later in the HOBOware Conductivity Assistant 4 When using the Conductivity Assistant look for the spot in the data where there are three similar readings in a row and link the last of those readings to the meter reading The time you noted may be slightly different than the logger time so looking for the three similar readings will help isolate the correct reading The Conductivity Assistant uses that value to calibrate the specific conductance and salinity readings for that data series Method 3 Taking a sample back to the office in a sealable jar to measure there recommended for locations with conductivity that is stable when you do not have a field meter or it is not convenient to access the logger 1 Place a sample of the water taken from next to the logger in a jar and immediately seal it to ensure that none of the water evaporates This allows the specific conductance and salinity of the sample to be maintained which in turn results in usable temperature and conductivity readings when you measure it with the meter at a later time 2 Write down the time you take the sample for use later in the HOBOware Conductivity Assistant www onsetcomp com 3 At the office measure the temp
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