EUTECH INSTRUMENTS CYBERCOMM 5000 FOR CYBERSCAN 5000 Bedienerhandbuch PDF herunterladen (Seite 171)

Instruction Manual CyberScan PC5500/ 5000

166

Conductivity Measurement

Conductivity electrodes consist of glass or epoxy bodies in which

platinum or platinised sensing elements and are designated two-cell

electrode has two such sensing elements and are designated two-cell

electrodes. The previous discussion has focused on this type of

electrode. Four cell electrodes are also available, and the theory and

application of these are in a separate section.

These sensors contact the solution whose conductivity value is

sought. The exact cell constant of the electrode must be determined

prior to measuring the sample. In essence, this is accomplished by

fixing the nominal cell constant of the electrode into the meter, and

recording the observed conductivity value associated with a standard

conductivity solution (usually a KCI solution) with a precisely known

value. The following calculation yields the actual cell constant.

K= standard value of solution (uS)/ observed value of solution (uS)

Fortunately, this CyberScan meter automatically does this calculation

for you by touching the std button.

To produce an appropriate current signal for the meter it is important

to choose an electrode with an appropriate cell constant. The

following table lists the optimum conductivity ranges for electrodes

with cell constants of 0.1, 1, and 10.

Cell Constant

Optimum Conductivity Range

2-cell

0.1

1.0

10.0

0.5 to 200 µS/ cm

0.01 to 2 mS/ cm

1 to 200 mS/ cm

Prior to use the electrodes should be conditioned in distilled or

deionized water for at least 10 minutes or in accordance with the

manufacturer’s instructions.

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EUTECH INSTRUMENTS CYBERCOMM 5000 FOR CYBERSCAN 5000 Bedienerhandbuch Seite 171