Xylem 6-Series Multiparameter Manual do Utilizador descarregar pdf (Página 340)

Percent Air Saturation Appendix J

YSI Incorporated Environmental Monitoring Systems Operations Manual J-3

%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.

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Xylem 6-Series Multiparameter Manual do Utilizador Página 340