YSI Professional Plus User Manual

Page 19

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After selecting your User ID and/or Probe ID if appropriate, highlight Do and

press enter.

Highlight DO % and press enter to confirm.

the instrument will use the internal barometer

during calibration and will display this value

in brackets at the top of the display. Highlight

Barometer and press enter to adjust it if needed.

If the barometer reading is incorrect, it is

recommended that you calibrate the barometer.

Note - the barometer should be reading “true”

barometric pressure (see Barometer section

for more information on “true” barometric

pressure). If the value is acceptable, there is

no need to change it or perform a barometer

calibration.

the Salinity value displayed near the top of the

screen is either the salinity correction value

entered in the Sensor menu or the Salinity

value as measured by the conductivity sensor

in use and enabled. If you are not using a

conductivity sensor, the Salinity correction

value should be the salinity of the water you

will be testing. Highlight Salinity and press

enter to modify this setting if necessary. See the

Salinity Correction section of this manual for

more information.

Wait for the temperature and Do% values under “Actual Readings” to stabilize,
then highlight Accept Calibration and press enter to calibrate. or, press Esc

to cancel the calibration. If User Field 1 or 2 are enabled in the GLP menu, you
will be prompted to select these inputs and then press Cal

to complete the

calibration. the message line at the bottom of the screen will display “Calibrating

Channel...” and then “Saving Configuration...”.

Calibrating Do% in Water Saturated Air:

2-Point Calibration with Zero Solution

Place the sensor in a solution of zero Do.

A zero Do solution can be made by dissolving approximately

8 - 10 grams

sodium sulfite (Na

) into 500 mL tap water or DI water. Mix the solution

thoroughly. It may take the solution 60 minutes to be oxygen-free.

Press Cal

. Highlight Probe ID or User ID if you wish to add, select, edit, or

delete an ID. Probe ID must be enabled in the System GLP menu to appear in

the Calibrate menu. When enabled, these IDs are stored with each calibration

record in the GLP file.

After selecting the Probe ID and/or User ID if appropriate, highlight Do and

press enter. Highlight Zero and press enter. Wait for the temperature and

Do% values under “Actual Readings” to stabilize, then press enter to Accept

Calibration. If User Field 1 or 2 are enabled, you will be prompted to select the
fields and then press Cal

to complete the calibration. the screen will then

prompt for a follow-up second point calibration.

Highlight DO% and press enter to continue with the next calibration point.

Rinse the sensor of any zero oxygen solution using clean water. then follow the

steps under Calibrating Do % in Water Saturated Air to complete the second

point.

Calibrating in mg/L or ppm as a titration:

1-Point Calibration

Place the sensor into an adequately stirred sample that has been titrated to

determine the dissolved oxygen concentration. Allow the sensor to stabilize.