Section 17 Glossary; Gas Units; Generic Terms And Definitions - Hach ORBISPHERE K-M1100 User Manual

Section 17 Glossary

17.1 Gas units

Unit
percentage, by weight. A concentration of 100% air corresponds to liquid saturated with air at current
% air pressure and temperature. The equivalent concentration of O
conditions.
percentage, by weight. A concentration of 100% O
% O
2
current pressure and temperature.
%Vbar ratio in percent between the partial pressure of gas measured and the atmospheric pressure
ratio in percent between the partial pressure of gas measured and the external pressure. Available when
%Vext
an external pressure sensor is present.
µg/L micrograms per liter
atm atmosphere
bar, mbar bar, millibar
volume of gas per kg of liquid. The volume of gas is calculated considering normal conditions
cc/kg
(T = 0°C, p = 1atm)
g/kg grams per kilogram
3
g/m grams per cubic meter
mg/L milligrams per liter
ml/L milliliters per liter
Pa, hPa, kPa Pascal, hecto Pascal, kilo Pascal
ppb parts per billion, by weight
ppm parts per million, by weight (same as mg/kg)
parts per million, per volume, barometric pressure referenced.
ppm Vb
= %Vbar / 10,000
parts per million, per volume, external pressure referenced.
ppm Ve
= %Vext / 10,000
psia pound per square inch, absolute
V / V volume per volume (ratio)

17.2 Generic terms and definitions

Terms
Absolute pressure
Accuracy of measurement
Analog output
ASCII
Baud rate
CIP
Concentration
Conductivity
FIFO (First In First Out)
Headspace
Limit of detection (LOD)
Master / Slave modes
Measurand
This is the total pressure in a system (i.e. relative pressure, plus atmospheric pressure).
The closeness of agreement between the result of a measurement and a true value of the
measurand.
A current signal that is a continuous function of the measured parameter.
American Standard Code for Information Interchange. A standard character-coding scheme used
by most computers to display letters, digits and special characters.
Baud rate means transmission speed (Unit: bits per second, bps ), especially for RS-232/422/485
interfaces.
Cleaning In Place.
The relative content of a component in a gaseous or liquid media.
The reciprocal of electrical resistivity.
FIFO is a concept to describe the behavior of a buffer. It means the data which entered first will
exit first.
The empty volume above a liquid or solid in a closed container.
Statistically, LOD = 3 STD (Standard Deviation) or 3Sigma as it is sometimes called.
A device operating as a master will poll one or more devices operating as a slave. This means a
slave device cannot volunteer information; it must wait to be asked for it.
A physical parameter being quantified by measurement.
Meaning
is approximately 20% O
2
corresponds to liquid saturated with pure O
2
Meaning
in normal
2
at
2
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