Choosing a Conductivity Logger: 5 Important Considerations

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Presented by: Paul GannettProduct Marketing Manager, Onset

• Accuracy considerations• Ease of deployment and data offload• Software capabilities• Cost of ownership• Deployment considerations

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5 Important ConsiderationsChoosing a Conductivity Logger:

• How prone is the sensor to drift? (Non-contact sensors have less drift than sensors that use electrodes)

• Does the logger software include compensation for measurement drift from fouling?

• How easy is it to clean the sensor of any fouling?

• What is the logger’s temperature accuracy and response time? … Every 0.5C of temperature error causes 1% error in specific conductance

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Accuracy considerationsChoosing a Conductivity Logger

• Does the logger sink or float? Deployment in wells is easier if the logger sinks

• The smaller the logger, the easier it is to deploy

• How is the logger be mounted? An eyelet makes it easy to hang in wells• Waterproof data shuttle for

convenient offload

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Ease of deployment and data offloadChoosing a Conductivity Logger

Conductivity logger

Water level

Ground level

Look for software that makes it easy to configure your logger and analyze data:

• Conversion to specific conductance with choice of temperature compensation methods

• Entering field calibration readings – preferably from both the start and end of deployment

• Multi-logger graphing and analysis• Easy data export• Project save and recall

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Software capabilitiesChoosing a Conductivity Logger

• Software that can compensate for drift means you don’t have to go into the field as often to take calibration readings

• Regular sensor cleaning extends the logger’s life – look for one that is easy to clean

• Replacement batteries and sensors extends the life of your logger• Using a waterproof shuttle avoids risking your laptop in the field• The cost of stand-alone conductivity loggers is coming down,

with some below $700

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Cost of ownership

Be sure to consider features that save you time or extend the life of your logger

Choosing a Conductivity Logger

• The logger should be placed in a location that has good, continuous water flow, if possible

• Mount the logger so that the sensor face is vertical to water flow to prevent air bubbles from forming on the sensor

• Keep the logger at least an inch from metal surfaces

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Deployment considerations - MountingChoosing a Conductivity Logger

You will need a calibrated conductivity meter for field measurements

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Deployment Considerations - MaintenanceChoosing a Conductivity Logger

Clean the sensor with a cotton swab and mild detergent whenever possible – particularly in fouling environments

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HOBO Conductivity LoggerChoosing a Conductivity Logger

The HOBO U24 Conductivity Logger is a high-accuracy, cost effective data logger for measuring conductance and temperature in streams, lakes, and other freshwater sources.

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HOBO Conductivity LoggerChoosing a Conductivity Logger

• Durable, non-corrosive Delrin® housing• Non-contact sensor that is easy to clean• Optical interface provides high-speed,

reliable data offload in wet environments• Compatible with HOBO Waterproof Shuttle

for easy and reliable data retrieval• HOBOware Pro software provides drift

compensation using calibration points from the start and end of each deployment and accurate conversion to specific conductance for the water type

• $699

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Questions and Answers

Choosing a Conductivity Logger

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Questions and Answers

Choosing a Conductivity LoggerWebinar

To discuss your upcoming monitoring project in greater detail, please contact us:

Tel. (800) LOGGERS (564-4377)Email: sales@onsetcomp.comOr visit us at onsetcomp.com

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HOBO U24 – Main SpecificationsChoosing a Conductivity Logger

Price $699

Ranges 0 to 1000 us/cm and 0 to 10,000 us/cm

Memory 18,500 temperature and conductivity measurements when using one conductivity range; 14,400 sets of measurements when using both conductivity ranges (64kbytes)

Sample rate 1 second to 18 hrs., fixed or multiple-rate sampling with up to 8 user-defined sampling intervals

Battery 3.6 Volt lithium battery

Battery Life 3 years (at 1 minute logging), typical

Maximum Depth 70m (225 ft)

Operating Range 0⁰ to 50⁰C (32⁰ to 122⁰F); non-freezing

Weight 193 gm (6.82 ounces)

Size 3.18 cm diameter x 16.5 cm, with 6.3 mm mounting hole