Calibration (Cont) - Hach Ultra ORBISPHERE 511 Quick Manual

Calibration Results
A calibration screen will be displayed showing
current measurement data which is continually
refreshed.
The value "% ideal current" is a percentage of the
c u r r e n t a g a i n s t t h e i d e a l c u r r e n t f o r t h e
membrane type selected. If this percentage is not
within the accepted range, an error message is
displayed and the calibration process fails. A
warning message can be displayed when this
value is close to the boundaries, but when
calibration can be accepted.
The message is first displayed in the result box.
The dialog box with the error message or the
warning is displayed when the finish button is
pressed.
The value "% last calibration" shows the ratio
between current measurement and the previous
sensor calibration.
The value "% variation" indicates the variation
during the last 3 measurements, which is the
stability of the measurements. A variation as low
as possible is needed for a precise calibration
T he display sho ws t he actua l calib ra tio n
p a r a m e t e r s , a n d t h e a c t u a l r e a d i n g s
(temperature, barometer, current).
In case of a calibration failure, consider replacing
the membrane. See the EC Sensor Maintenance
Manual for details.

Calibration (cont)

Verification
Similar to the calibration procedure, but for
verification of the actual calibration values. The
result of the measurements made during the
verification is not stored and the actual calibration
data is not modified.
O Sensor Calibration
2
The sensor is in contact with either:
•
•
O
In Air Calibration
2
This calibration procedure places the O
water-saturated air, to provide a known oxygen
reference against which to calibrate.
Dry the sensor thoroughly, before placing the
sensor storage cap under tap water. Shake off
any excess water, but leave a few drops inside
the cap. Verify that the screw-on protection cap is
in place on the sensor head.
Then, loosely place the storage cap back on the
sensor, holding it in place with a few turns of its
collar.
Set the calibration parameters accordingly and
press calibrate.
O Direct Calibration
2
This procedure calibrates the oxygen sensor
against a liquid sample containing a known level
of dissolved O
The instrument displays the sensitivity of the
sensor as a percentage of the sensitivity
determined when calibration was last performed.
Set the calibration parameters accordingly and
press calibrate.
Air at atmospheric pressure (In Air)
O at known concentration (Direct value).
2
flowing through the sample line.
2
sensor in
2
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