YSI 85 - Manual (Page 15)

YSI, Incorporated Model 85 11
SECTION 5 CALIBRATION
5.1 CALIBRATION OF DISSOLVED OXYGEN
To accurately calibrate the YSI Model 85 you will need to know the approximate altitude of
the region in which you are located.
1. Ensure that the sponge inside the instrument's
calibration chamber is wet. Insert the probe into
the calibration chamber.
2. Turn the instrument on by pressing the
ON/OFF button on the front of the instrument.
Press the MODE button until dissolved oxygen
is displayed in mg/L or %. Wait for the
dissolved oxygen and temperature readings to
stabilize (usually 15 minutes is required).
3. Use two fingers to press and release both the
UP ARROW and DOWN ARROW buttons at the same time.
Calibration/Storage
Chamber
4. The LCD will prompt you to enter the local altitude in hundreds of feet. Use the arrow
keys to increase or decrease the altitude. When the proper altitude appears on the LCD, press
the ENTER button once.
EXAMPLE: Entering the number 12 here indicates 1200 feet.
5. The Model 85 should now display CAL in the lower left of the display, the calibration
value should be displayed in the lower right of the display and the current % reading (before
calibration) should be on the main display. Make sure that the current % reading (large
display) is stable, then press the ENTER button. The display should read SAVE then should
return to the Normal Operation Mode.
Each time the Model 85 is turned off, it may be necessary to re-calibrate before taking
measurements. All calibrations should be completed at a temperature which is as close as
possible to the sample temperature. Dissolved oxygen readings are only as good as the
calibration.