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Chapter 4
Calibration
4.1 Conductivity
Calibration
4.1.1 Calibration Overview
When the conductivity calibration is the only calibration
performed, it will be applied to all measurement modes.
When a TDS calibration is performed, it will only be applied
to TDS measurements. When a salinity calibration is
performed, it will only be applied to salinity measurements.
The non-volatile meter memory retains the most recent,
active calibration data when powered off.
Perform a calibration with one to five conductivity
standards, one to five TDS standards and one salinity
standard. A maximum of one calibration point per range
can be performed for conductivity and TDS calibrations.
Range
Conductivity Range
#
r1
0.00 to 20.00 µS/cm
r2
20.01 to 300.0 µS/cm
r3
300.1 to 9999 µS/cm
r4
10.00 to 99.99 mS/cm
r5
100.0 to 500.0 mS/cm
Range
TDS Range
#
r1
0.00 to 10.00 ppm
r2
10.01 to 200.0 ppm
r3
200.1 to 9999 ppm
r4
10.00 to 99.99 ppt
r5
100.0 to 500.0 ppt
When the conductivity electrode is replaced, it is best to
clear the calibration log. Refer to the
detailed instructions.
For best results, periodic calibration with known, accurate
and fresh conductivity standards is recommended. Always
Automatic Calibration
Value at 25°C
none
84.00 µS/cm
1413 µS/cm
12.88 mS/cm
111.8 mS/cm
Clear Data
section for
use fresh conductivity standards. Select a conductivity
standard or standards that are closest to the expected
sample conductivity value or values. Thoroughly rinse the
conductivity electrode before calibration and between
samples with deionized water.
During the conductivity calibration, the meter will
automatically recognize conductivity standard values of
84 µS/cm, 1413 µS/cm, 12.9 mS/cm and 111.8 mS/cm
(values at 25°C).
The
Temperature Compensation Coefficient
Setup Menu will determine how the conductivity calibration
standards are displayed during the calibration.
• If temperature compensation is set to Off: Once the
calibration reading is stable, the meter will display
the conductivity standard value at its measured
temperature (conductance).
• If temperature compensation is set to On: Once the
calibration reading is stable, the meter will display
the temperature compensated conductivity standard
value, based on the
selected in the Setup Menu (15, 20, 25 or 30°C).
If the conductivity reading does not correspond with an
automatically recognized conductivity standard value
(within ±40% window), once the conductivity reading is
stable, the meter will display the theoretical value of the
conductivity standard according to the
Constant
value entered in the Setup Menu. The operator
must manually enter the conductivity standard value at the
measured temperature (conductance).
During calibration, each conductivity standard value can be
accepted or edited as needed. If the conductivity standard
value needs to be manually adjusted, use the or key
to edit the value of the conductivity standard at its
measured temperature.
After performing a one point conductivity calibration, the
meter will apply the resulting calibration factor across all
conductivity ranges. After performing a two, three, four or
five point conductivity calibration, the meter will apply the
resulting calibration factor of each conductivity standard to
its applicable conductivity range and apply the most
relevant calibration factor to any conductivity ranges for
which a standard was not used during calibration.
Press the "Cal" key to start and end the calibration. This
allows conductivity calibrations and TDS calibrations to be
performed using one to five points without having to
program the number of points before starting the
calibration.
Eutech EC 1720 Conductivity Meter
setting in the
Reference Temperature
Nominal Cell
25
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