YSI 52 - Manual (Page 12)

Calibration Section 3
3. Switch to CALIBRATE. The display will read:
C a l i b r a t e
i n p e r c e n t ?
Press SKIP. The display will read:
C a l i b r a t e
i n m g / L ?
Press CONFIRM to select mg/L calibration. A display similar to the one below will be
shown.
E n t e r c a l v a l u e
L a s t = 8 . 1 5 m g / L
4. Use ¿ and À to set the calibration value determined by Winkler titration. You may be
able to set the value more quickly by using the SKIP key to bring the value near the one
you want, then continuing with ¿ and À. Pressing SKIP once sets the value to the
saturation value of oxygen in water at the probe temperature. A display similar to the one
below will be shown.
E n t e r c a l v a l u e
S a t . = 8 . 5 8 m g / L
Pressing SKIP again sets the value to 0.00 mg/L. (See Zero Calibration, below.) Pressing
SKIP a third time brings it back to the last calibration value.
5. When the correct value is set, press CONFIRM. The display will show the legend
“Please wait” for a few seconds, and then display “Calibrated to...” To take dissolved
oxygen readings in mg/L, switch to O
2
-TEMP.
Note: Since there is no way to determine percent air saturation after a calibration in
mg/L, the % reading will be disabled.
3.6 ZERO CALIBRATION
In rare applications, the accuracy of the calibration can be improved by performing a zero
calibration along with one of the procedures discussed previously.
All oxygen probes have a small background current, even in the absence of oxygen.
Model 52 compensation is based on the average background current of YSI 5700 and
YSI, Incorporated Model 52 8