wtw Multi 350i, Operating Manual

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Multi 350i Operation
53
4.6.4 DO calibration
Why calibrate? DO sensors age. This changes the slope of the DO sensor. Calibration
determines the current slope of the sensor and stores this value in the
instrument.
When to calibrate?
!
After connecting another DO sensor
!
When the sensor symbol flashes (after the calibration interval has
expired).
Calibration datasets The Multi 350i administrates three sets of calibration data:
Sensors of different types can be calibrated separately from each other.
When a sensor of one type is calibrated, the calibration data of the oth-
er types remain stored. The Multi 350i recognizes the type of the con-
nected sensor and automatically uses the correct calibration data.
Calibration procedure The Multi 350i provides 2 calibration procedures:
!
Calibration in water vapor-saturated air.
Use an OxiCal
®
air calibration vessel for the calibration.
!
Calibration via a comparison measurement (e.g. Winkler titration ac-
cording to DIN EN 25813 or ISO 5813). At the same time, the rela-
tive slope is adapted to the comparison measurement by a
correction factor. When the correction factor is active, the
[Factor] in-
dicator appears in the measuring window.
AutoRead The calibration procedure automatically activates the AutoRead func-
tion.
Display calibration data
and output to interface
You can have the data of the last calibration displayed (see
section 4.8.5). Subsequently, you can transmit the displayed calibra-
tion data to the interface, e. g. to a printer or PC, with the
<PRT> key.
Note
The calibration record is automatically transmitted to the interface after
calibrating.
!
Set 1 for the type, "CellOx": – CellOx 325, or
– StirrOx G
!
Set 2 for the type, "DurOx": – DurOx 325
!
Set 3 for the type, "ConOx": – ConOx