Chapter 3
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Meter Setup Menus
Solution (25 °C to 50 °C)
Temperature Coefficient (% / °C)
Dilute Ammonia
1.88
5% NaOH
1.72
10% HCl
1.32
5% Sulfuric Acid
0.96
•
nLFn (non-linear ultra pure non-degassed water) – applies a non-constant correction factor
to pure water samples that have a varying response to changes in temperature. This mode
is for temperature compensated readings of low conductivity waters that are in equilibrium
with the carbon dioxide in air, such as pure waters reading near 1 μS/cm at 25 °C and
natural waters having a composition comparable to natural ground, well or surface waters.
•
Off - no temperature correction is applied and the actual conductivity value is displayed at
the measured sample temperature.
Salinity Type
Orion Star A222 conductivity meters offer one salinity type: practical salinity. Practical salinity
measurements are based on relating the sample measurement to the reading of a standard
potassium chloride (KCl) solution at 15 °C. Orion Star A220 series conductivity meters will
automatically temperature compensate and report the expected practical salinity result as
practical salinity units (psu) at 15 °C when using a conductivity sensor with built-in temperature.
TDS Factor Setting
Orion Star A222 conductivity meters measure TDS as the total amount of dissolved inorganic
material in a solution. The dissolved inorganic material carries a current that is measured by the
conductivity sensor. Since there is a direct relationship between conductivity and TDS,
conductivity readings are used to estimate the presence of inorganic material using the TDS
factor entered in the setup menu.
The standard method of determining TDS involves evaporating a sample to dryness at 180 °C
and weighing the residue. The TDS factor is calculated by taking the residue weight and
dividing it by the sample conductivity. Subsequent conductivity readings are multiplied by the
TDS factor to determine the TDS value of the sample.
Cell Type Setting
Orion Star A222 conductivity meters accept 2-cell and 4-cell conductivity sensors and allows
the type of conductivity sensor to be set as Standard (most conductivity sensors) or USP (for
the ultra pure water conductivity sensor, Catalog Number 013016MD, when disabling
temperature compensation).
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Orion Star A220 Series Portable Meter User Manual
Thermo Scientific
Содержание Orion Star A220 Series
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