pH/Oxi 340i
Operation
33
4.4
Dissolved oxygen
4.4.1
General information
Note
D. O. measurements with the pH/ Oxi 340i can only be carried out using
a CellOx 325 or StirrOx G D. O. probe. The stirrer of the StirrOx G D.
O. probe has to be supplied with voltage separately using the
NT/pH Mix 540 power supply.
You can measure the following variables:
l
D. O. concentration
l
D. O. saturation
The pH/Oxi 340i handheld meter is equipped with the following func-
tions:
l
AutoRange (automatic measurement range selection),
l
The AutoRead function (drift control) for checking the stability of the
measurement signal. This ensures the reproducibility of the mea-
surement signal. For details of how to switch the AutoRead function
on/off, see page 36.
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.
Preparatory activities
Perform the following preparatory activities when you want to measure:
Note
Incorrect calibration of D. O. probes will result in incorrect measured
values. Calibrate at regular intervals.
1
Connect the D. O. probe to the measuring instrument. The in-
strument automatically switches over to D. O. measurement
(O
2
status display).
If the D. O. probe is already connected, press the <M> repeat-
edly until the O
2
status display appears.
2
Calibrate or check the measuring instrument with the probe.
How to calibrate is described in section 4.4.5 from page 37.
3
Immerse the D. O. probe in the test sample.
4
Use <
▲
> <
▼
> to toggle between the measuring modes, D. O.
concentration (mg/L) and D. O. saturation (%).
