Ysi 52 Manuel d'utilisateur télécharger pdf (Page 13)

Calibration Section 3

5900 Series probes. This is the default zero value. Although using this average will result

in errors with probes whose background current differs from the average.

Note: Errors will be insignificant in most applications. See Discussion of Measurement

Errors.

For highest accuracy measurements, a zero calibration should be performed to

compensate for the specific background current of the probe in use.

To calibrate to a true zero, place the probe in a zero oxygen environment and adjust the

calibration value to zero.

A standard method for creating such an environment is to dissolve in water (preferably

the water should come from the sample to be measured) excess sodium sulfite (Na

and a trace of cobalt chloride (CoCl

). These chemicals will remove all oxygen from the

sample (See Standard Methods for the Examination of Water & Wastewater, 17th

edition, 1989, page 4-161.) Alternatively, you may place the probe in 100% nitrogen gas.

Place the probe in the zero oxygen sample, switch to O

-TEMP and allow at least 20

minutes for the probe to come to equilibrium.

Switch to CALIBRATE. The display will show:

Press CONFIRM to select percent calibration. A display similar to the one below will be

shown:

C a l i b r a t e

i n p e r c e n t ?

E n t e r c a l v a l u e

L a s t = 9 2 . 5 %

Press SKIP twice to set the calibration value to 0.0%. The following display will be

shown.

E n t e r c a l v a l u e

Z e r o = 0. 0 %

Press CONFIRM to calibrate to zero. The display will ask you to wait, then show

"Calibrated to 0.0 %." After zeroing, rinse the probe thoroughly to remove any residual

trace of chemicals.

The Model 52 is calibrated at two points: the calibration value you select, and its default

zero.

YSI, Incorporated Model 52 9

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Ysi 52 Manuel d'utilisateur Page 13