H83.0.01.6C-6
Operating manual GMH 5450
page 7 of 20
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5 Start Operation
Connect electrodes, turn device on via
key.
After segment test
the device displays some information on its configuration:
if zero point or slope correction is active
(see chapter 10
Adjustment of temperature input)
If a measuring cell will be connected to the instrument the first time or if the measuring cell was changed, the
referring cell parameters in the instrument have to be entered, before measuring:
,
und
. Please refer to chapter
Fehler! Verweisquelle konnte nicht gefunden
werden.
Configuration
After that the device is ready for measuring.
6 Principles of the measurements
6.1 Basics about conductivity
Definition of conductivity : The ability of a material to conduct electric current:
l
:
length of the material
A
:
diameter
R
:
measured resistance
Unit
, common for liquids:
and
The conductivity is the reciprocal value of the resistivity.
(The conductance is the reciprocal value of the measured resistance R)
6.2 Measuring ranges and cell constants
Different measuring ranges can be realized depending on the used electrode. Therefore the device offers
four cell constant ranges to choose, depending on the correspondent cell constant K:
CELL rAnG
Selectable cell constant K
Application
0.01
0.004000 - 0.01500
0•1/cm
Ultra-pure water, electrodes with K = 0.01
0.1
0.04000 - 0.150
00•1/cm
Ultra-pure water, electrodes with K = 0.1
1
0.4000 - 1.500
0•1/cm
Standard electrodes e.g. with K= 0.55 or K=1
10
4.000 - 15.0
00 •1/cm
Electrodes with K=10 (for extremely high conductivities)
The cell constant can be selected manually in the configuration menu (see chapter 7
“Configuration”) or with
the adjustment/calibration function. Then there are two possibilities:
- automatically with an reference solution (temperature compensated)
- adjustment/calibration of the displayed value if actual value of solution is known
6.3 Conductivity measurement
The conductivity measurement is a rather uncomplicated measurement. The standard electrodes are stable
for a long time if used correctly and can be adjusted by an integrated Cal-function.
Attention:
The device covers a wide measuring range, however a electrode suitable for the
measuring range has to be used.
Range
CELL
- rAnG
1
2
3
4
5
0.01
0.000 - 5.000 µS/cm 0.00 - 50.00 µS/cm 0.0 - 500.0 µS/cm
0 - 5000 µS/cm
0.00 - 50.00 mS/cm
0.1
0.00 - 50.00 µS/cm 0.0 - 500.0 µS/cm
0 - 5000 µS/cm
0.00 .. 50.00 mS/cm 0.0 - 500.0 mS/cm
1
0.0 - 500.0 µS/cm
0 - 5000 µS/cm
0.00 - 50.00 mS/cm 0.0
– 500.0 mS/cm 0 - 1000 mS/cm
10
0 - 5000 µS/cm
0.00 - 50.00 mS/cm 0.0 - 500.0 mS/cm
0
– 1000 mS/cm
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If the range selection is set to „Auto Range“, the range with the best resolution is automatically selected.
However, logger or interface operation requires a manual/fixed selection of the measuring range from the
table above (No logger/interface operation with Auto-range!).
