Taking Measurements; Dissolved Oxygen - YSI Professional Plus User Manual

After selecting your User ID and/or Probe ID if
appropriate, highlight Ammonium, Nitrate, or
Chloride to access the appropriate calibration,
and press enter. the parameter you want
to calibrate may appear under ISE1 or ISE2
depending on your cable type and setup. the
message line will show the instrument is ready
for the 1st calibration point.
the instrument will display the calibration value
at the top of the screen. If necessary, highlight
the Calibration value and press enter to input the correct value.
once the readings stabilize, highlight Accept Calibration and press enter to
accept the first calibration point. the message line will then display "Ready for
point 2".
If you do not wish to perform a second point, press Cal
calibration. If User Field 1 or 2 are enabled, you will be prompted to select these
fields and then press Cal to finalize the calibration. Alternatively, you may
press Esc to cancel the calibration.
to continue with the 2nd point, rinse the sensor with clean water, then dry it
before placing it in the second calibration standard. Allow at least 1 minute
for temperature equilibration before proceeding. the instrument will display
the second calibration value at the top of the screen. If necessary, highlight the
Calibration value and press enter to input the correct buffer value. once the
readings stabilize, highlight Accept Calibration and press enter to confirm the
second calibration point. the message line will then display "Ready for point 3"
and you can continue with the 3rd calibration point if desired.
If you do not wish to perform a 3rd calibration point, press Cal
the calibration. If User Field 1 or 2 are enabled, you will be prompted to select
these fields and then press Cal
may press Esc to cancel the calibration.
AMMoNIUM (NH4+) , NItRAtE (No3-), AND CHLoRIDE CL-
3-PoINt
A 2-point calibration without chilling a third calibration solution is extremely
accurate and is the preferred method. If you must perform a 3-point calibration,
the following procedure requires one portion of the high concentration calibration
solution and two portions of the low concentration calibration solution. the
to finalize the
to complete
to finalize the calibration. Alternatively, you
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high concentration solution and one of the low concentration solutions should
be at ambient temperature. the other low concentration solution should be
chilled to less than 10 °C prior to calibration.
WARNING: The chilled calibration solution MUST BE CHILLED
u
TO AT LEAST 5 °C COOLER THAN THE 1ST CALIBRATION
POINT, otherwise the 1st point will be OVERRIDDEN.
Follow the procedure for a 2-point cal. After the second calibration point is
complete, the message line with state 'Ready for point 3".
amount of chilled 1 mg/L standard (10 mg/L for the chloride) into a clean, dry
or pre-rinsed calibration cup. Carefully immerse the sensor into the solution.
Allow for temperature equilibration. If necessary, highlight Calibration value
and press enter to manually enter the 3rd buffer value. once the readings are
stable, highlight Accept Calibration and press enter to confirm. Press Cal
to complete the calibration. If User Field 1 or 2 are enabled, you will be
prompted to select these fields and then press Cal
Alternatively, press Esc to cancel the calibration.
t A K I N G M E A S U R E M E N t S
to obtain the most accurate readings, be sure the instrument is calibrated before

taking measurements.

dIssolVed oxyGen

turn the instrument on and wait 5-15 minutes if using a polarographic sensor.
If using a field cable/sensor, install the sensor guard to protect the sensor and
membrane. Place the probe in the sample to be measured and give the probe
a quick shake to release any air bubbles. Allow the temperature readings to
stabilize. Next, stir the probe in the sample to overcome the stirring dependence
of the dissolved oxygen sensor. You must provide at least 3 inches per second
for 2.0 PE membranes, 6 inches per second for 1.25 PE membranes, and 12
inches per second for teflon® membranes. once the values plateau and stabilize,
you may record the measurement and/or log the data set. the dissolved oxygen
reading will drop over time if stirring is ceased.
If placing the Do sensor into a stream or fast flowing waters it is best to place it
perpendicular to the flow and Not facing into the flow.
If using the Do sensor in an aeration tank/basin, it is helpful to make sure
bubbles do not burst on the membrane since this may cause unstable readings.
You should be able to prevent this by pointing the sensor upwards so it's facing
Place the proper
to finalize the calibration.
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