Xylem ConOx - Manual (Page 9)

ConOx Measuring / Operation
33
Unscrewing the
DO module
Unscrew the cap nut and remove the DO module from the conductivity basic
module.
Caution
Inappropriate handling can lead to the release of electrolyte solution.
When unscrewing the DO module only turn the cap nut (not the
membrane cap!).
3.2.3 Preparing the measuring operation
Connect the sensor to the measuring instrument. The sensor is immediately
ready to measure. It is not necessary to polarize the DO module.
4 Measuring / Operation
4.1 Calibration
To calibrate for DO measurements, use the OxiCal
®
-CX calibration and
storage vessel. If the A 325/K or A 325/S armoring is used, you have to
remove the protective hood and fixing nut of the armoring first.
When determining the cell constant, observe the respective minimum
immersion depth with the closing cap or D. O. module screwed on (important:
the temperature sensor must be submersed). The minimum immersion
depths are given in chapter 7 T
ECHNICAL DATA .
Note
Please read the course of the calibration in the operating manual of the mea-
suring instrument.
4.2 Measuring
Please always observe the required minimum immersion depth and the
minimum approach flow that is important for DO measurements (see
chapter 7 T
ECHNICAL DATA ).
Minimum
approach flow for
DO measurements
The minimum flow can be provided in different ways, e. g.:
l
The flow of the water to be measured is sufficient (aeration tank, water
pipe, stream)
l
Slowly pull the sensor through the water by hand (lake, container), or
l
Use a flow aid, e. g. a magnetic stirrer with stirring device or a battery stir-
rer (see chapter 8 W
EAR PARTS AND ACCESSORIES )
Note
When using the BR 325 battery stirrer, please make sure that the protective
pipe already has the groove in the area of the conductivity basic module (from
the year of manufacture, 2004).