YSI 6 series User Manual page 340

Percent Air Saturation Appendix J
%Local" values. For example, assume that the temperature of the calibration standard is 21 C (where air
saturation at 760 mm Hg is 8.915 mg/L) and that the oxygen content of the solution has been determined to
be 7 mg/L by Winkler titration. Assume also that the local barometric pressure was entered as 700 mm at
the last "DOsat %" calibration. After the new "DO mg/L" calibration, the "DO mg/L" value will be set to
7.00, the "DOsat %" value will be set to (7/8.915)*100 = 78.5, and the "DOsat %Local" will be set to
(760/700)*78.5 = 85.2.
NOTE: As pointed out above, it is important to realize that UNLESS THE BAROMETRIC PRESSURE IS
KNOWN FOR EVERY DO READING AFTER CALIBRATION, the values of "DOsat %" and "DOsat
%Local" will be incorrect if the barometric pressure has changed since calibration. Thus, even if the
barometer had been input at the time of a mg/L calibration (a method used by some instrument
manufacturers, the values of "DOsat %Local" will still not be exactly accurate after calibration.
Activation of the "DOsat %Local" or "ODOsat %Local" Parameter
On receipt of your sonde or after upgrading your 6-series software to Version 2.13 or higher, the "DOsat
%Local" or "ODOsat %Local" parameter will NOT appear in your Report menu. To activate the
parameter, it is necessary to exit the menu structure of the sonde software to the command line prompt
("#"). The "#" sign appears after you press Esc from the Main menu and then answer "Y" to the question,
"Exit menu (Y/N)"? Once the "#" prompt is shown on the display, type "dolocal 1" as shown in the
display below and press Enter. The screen will show "OK" to indicate that the action was successful and
return another "#" sign as shown. Then type "menu" at the second "# sign and press Enter to return to the
sonde software menu structure.
After taking the above action the parameter "DOsat %Local" or "ODOsat %Local", depending on the type
of DO sensor used in your sonde, will be present in your Report menu. If you want to remove the
parameter, return to the "#" prompt, type "dolocal 0", and press Enter.
YSI Incorporated Environmental Monitoring Systems Operations Manual J-3