Xylem ProLab 4000 MULTIPARAMETER BENCHTOP METER User Manual

Page 204

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ProLab 4000

204

ba75646e02

01/2010

Glossary

Adjusting

To manipulate a measuring system so that the relevant value (e. g.
the displayed value) differs as little as possible from the correct value
or a value that is regarded as correct, or that the difference remains
within the tolerance.

AutoRange

Name of the automatic selection of the measuring range.

Calibration

Comparing the value from a measuring system (e. g. the displayed
value) to the correct value or a value that is regarded as correct. Of-
ten, this expression is also used when the measuring system is ad-
justed at the same time (see adjusting).

Cell constant, k

Characteristic quantity of a conductivity measuring cell, depending
on the geometry.

Channel

A channel is an indication on the display that corresponds to a phys-
ical connection at the meter.

The connections for similar sensor types are numbered on the meter
(pH/U/ISE Probe 1, pH/U/ISE Probe 2). To secure the assignment of
connection and channel on the display, the channel is numbered on
the display.

Conductivity

Short form of the expression, specific electrical conductivity. It is a
measured value of the ability of a substance to conduct an electric
current. In water analysis, the electrical conductivity is a dimension
for the ionized substances in a solution.

Electrode zero point

The zero point of a pH electrode is the pH value at which the electro-
motive force of the pH electrode at a specified temperature is zero.
Normally, this is at 25 °C.

Electromotive force of an

electrode

The electromotive force (voltage) U of the electrode is the measur-
able electromotive force of an electrode in a solution. It equals the
sum of all the galvanic voltages of the electrode. Its dependency on
the pH results in the electrode function, which is characterized by the
parameters, slope and zero point.

Junction

The junction is a porous body in the housing wall of reference elec-
trodes or electrolyte bridges. It forms the electrical contact between
two solutions and makes electrolyte exchange more difficult. The ex-
pression, junction, is also used for ground or junction-less transi-
tions.

Measured parameter

The measured parameter is the physical dimension determined by
measuring, e. g. pH or conductivity.

Measured value

The measured value is the special value of a measured parameter
to be determined. It is given as a combination of the numerical value
and unit (e. g. 3 m; 0.5 s; 5.2 A; 373.15 K).

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