HOBO Dissolved Oxygen Logger (U26-001) Manual
4
3.
Wet the small sponge with fresh water. Squeeze out any
excess water.
4.
Place the sponge in the end of the calibration boot.
5.
Insert the logger in the calibration boot so that there is
approximately a 1 cm (0.5 inch) overlap between the end of
the boot and the body of the logger. This will ensure there
is enough space between the end of the logger and the
sponge (the logger should not be pressed up tightly against
the sponge).
6.
Wait for approximately 15 minutes until the logger reaches
temperature equilibrium (and less than 30 minutes so the
logger does not go to sleep).
7.
Click the “Get DO value from the logger” button to display
the 100% saturation results. You can click this button as
often as needed. The results are updated each time you
click the button. To check for equilibrium, click the “Get DO
value from the logger” button several times in a row to
check the current “DO Conc from logger at 100%
Saturation” value. If the value remains the same or varies
very little with each button click, then temperature
equilibrium has likely been reached.
8.
When you are satisfied with the results displaying in the
“Step 1: 100% Saturation” tab, click the Next button to
proceed to “Step 2: 0% Saturation.”
Step 2: 0% Saturation (optional)
If the logger will be deployed in water with DO levels greater
than 4 mg/L, click the “Skip this Step” button. Otherwise,
continue with the following procedure.
1.
Make sure the logger either has the protective guard or the
anti-fouling guard installed (whichever guard you plan to
use in the deployment) so that the sensor is covered.
2.
Pour the sodium sulfite into the beaker so that it is about
two-thirds full.
3.
Place the sensor end of the logger into the solution so that
the entire protective guard or anti-fouling guard and at
least 2.5 cm (1 inch) of the logger body are submerged in
the beaker. Allow it to rest on the bottom of the beaker.
4.
Wait for approximately 15 minutes until the logger reaches
temperature equilibrium (and less than 30 minutes so the
logger does not go to sleep).
5.
Click the “Get DO value from the logger” button to display
the 0% saturation results. As with the 100% calibration, you
can click this button as often as needed. The results are
automatically updated each time you click the button. If the
value remains the same or varies very little with each
button click, then temperature equilibrium has likely been
reached.
6.
When you are satisfied with the results displaying in the
“Step 2: 0% Saturation” tab, click the Next button to
proceed to “Step 3: Finish.”
Step 3: Finish
The results from the first two steps are displayed as well as the
overall calibration results and the new gain and offset
adjustment values. If you are satisfied with the results, click the
“Send Calibration to Logger” button. The logger will then be
calibrated based on the new values. These values will not take
effect until the logger is launched. If you do not want to save
these values, click Close to cancel the calibration and revert
back to the last saved logger values. Or, click “Reset to Factory
Defaults” to return to the original values. If you performed Step
2, then remove the logger from the solution and thoroughly
rinse it with fresh water to remove any excess sodium sulfite.
See
Maintenance
for additional details on cleaning the logger.
Launching the Logger
After calibrating the logger, it needs to be launched to
configure it before taking it to the field for deployment. Once
launched, the logger will 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 logger activity, such as Bad Battery or Host
Connected. Events help you determine what was happening
while the logger was logging. To launch the logger:
1.
With the logger connected to the computer, open
HOBOware. From the Device menu, select Launch.
2.
Select both the DO and Temperature channels to log.
Note:
HOBOware provides the option of recording the current
battery voltage at each logging interval, which is disabled by
default. Recording battery life at each logging interval takes
up memory and therefore reduces logging duration. It is
recommended that you only record battery voltage for
diagnostic purposes. Even with the channel disabled, a bad
battery event will still be recorded.
3.
Select a logging interval.
4.
Choose when to start logging and click the Start button.
5.
Remove the logger from the coupler and screw the
communications cap back on the logger.
IMPORTANT
: If this is the first launch with a new sensor cap,
the sensor cap will expire six months (plus a one-month grace
period) from the time of the first sensor reading. Two caps per
year are required for year-round deployment.
Deploying the Logger
The logger is designed to be easy to deploy in many
environments. Follow these guidelines when deploying it:
•
Remove the calibration boot before deploying the logger.
•
Make sure the logger is located where it will receive an
unrestricted flow of the water being monitored to the
sensor.
•
Make sure the logger is fully submerged and not in direct
sunlight to minimize temperature changes that are
unrelated to water temperature.
•
When deploying the logger in rivers, streams, and ponds,
insert the logger in a PVC or ABS pipe for protection from
debris (if possible). The pipe should have enough holes to
ensure good circulation of water to the sensor.
•
If possible, position the logger so the sensor face is
oriented vertically. After deploying in the water, move
the logger around slightly to eliminate any bubbles that
may have formed.
