Xylem MULTI 3400 MULTI-PARAMETER METERS - Manual (Page 26)

Operation Multi 3400i
26
4.3 Dissolved oxygen
4.3.1 General information
Note
D. O. measurements with the Multi 3400i 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:
z D. O. concentration
z D. O. saturation
The measuring instrument is supplied with the following functions:
z AutoRange (automatic switchover of the measurement range),
z 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 29.
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.
Temperature sensor The D. O. probe has an integrated temperature sensor that always
measures the current temperature of the test sample.
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 sensor.
How to calibrate is described in section 4.3.5 from page 20.
3 Use <
▲> <▼> to toggle between the measuring modes, D. O.
concentration (mg/L) and D. O. saturation (%).