wtw Oxi 197i, Operating Manual, Page: 16 / 63

Operation Oxi 197i
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4.2 Measuring
4.2.1 General information
You can measure the following variables:
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D. O. concentration
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D. O. saturation
The measuring instrument is supplied with the following functions:
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AutoRange (automatic switchover of the measurement range). If a
measuring range is exceeded, AutoRange causes the measuring in-
strument to change automatically to the next higher measuring
range and back again. Therefore, the instrument always measures
in the measuring range with the highest possible resolution. The
function can be switched off.
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The AutoRead function (drift control) for checking the stability of the
measurement signal. This ensures the reproducibility of the measur-
ing signal. For details of how to switch the AutoRead function on/off,
see page 19.
Preparatory activities Perform the following preparatory activities when you want to measure:
Note
Incorrect calibration of D. O. sensors will result in incorrect measured
values. Calibrate at regular intervals.
Note
The measuring instrument automatically recognizes the type of the D.
O. sensor (CellOx 325 or DurOx 325).
Temperature sensor The D. O. sensor has an integrated temperature sensor that always
measures the current temperature of the test sample.
Warning
When connecting an earthed PC/printer, measurements cannot be per-
formed in earthed media as incorrect values would result. The RS232
interface is not galvanically isolated.
1 Connect the D. O. sensor to the measuring instrument (see
section 1.3 S
OCKET FIELD
).
2 Calibrate or check the measuring instrument with the D. O.
sensor. How to calibrate is described in section 4.3.
3 Select the measuring mode with <M> .