OTT Hydrolab DS5, User Manual

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Glossary & Abbreviations
Hysteresis error
—The maximum separation due to hysteresis between upscale-and
downscale-going indications of a measured value. A difference in parameter readings
which occurs due to a variation in the conditions under which the sensor approached the
readings. (See: Response time)
Isopotential point
—The point at which the ion activity is the same on both sides of a
sensor membrane. At the isopotential points, there is a zero potential across the
membrane. The observed potential of the sensor may not be zero, due to the differences
in reference electrodes.
Milliohm (m Ω )
—Unit of resistance (not conductivity or conductance.)
MilliSiemens (mS) = millimho (m )
—Units of electrical conductance.
Millimho (m )
—(See: MilliSiemens)
Molar concentration
—Molar solution: Aqueous solution that contains one mole (unit =
gram-molecular weight) of solute in one liter of water. For example: KCl (potassium
chloride) molar concentration.
Multiprobe
—The combination of several sensors, electrodes, or probe assemblies into a
complete, stand-alone piece of equipment which simultaneously measures several
parameters for profiling, spot-checking, or logging readings and data. A multiprobe is a
multi-parameter instrument.
Nitrate (NO
3–
)
—Nitrate is the most oxidized form of nitrogen, and is the primary form of
biologically available nitrogen present in aerobic environments. Nitrate is a less toxic form
of nitrogen than ammonia, and is readily assimilated by plants and bacteria.
Oxidation reduction potential (or ORP)
—(See: Redox potential)
Parameter
—A quantity which is constant under a given set of conditions, but may be
different under other conditions.
pH
—Describes the hydrogen-ion activity of a system: pH 0–7: acid solution, pH 7: neutral,
pH 7–14: alkaline (or basic) solution. The "p" in pH stands for power (puissance) of the
hydrogen ion (H+) activity. pH is a major factor affecting the availability of nutrients to
plants and animals. It controls in part the concentration of many biochemically active
substances dissolved in water, and it affects the efficiency of hemoglobin in the blood of
vertebrates (e.g. fish) and invertebrates (e.g. shrimp), as well as the toxicity of pollutants.
Probe
—A small tube containing the sensing elements of electronic equipment. The probe
is an essential part of the water quality monitoring system, since it obtains measurements
and data which can be stored, analyzed, and eventually transferred to a computer.
Probe assembly
— (See: Assembly)
Profiling
—Electrical exploration wherein the transmitter and receiver are moved in unison
across a structure to obtain a profile of mutual impedance between transmitter and
receiver = lateral search. In water quality, this term is used as the contrary of unattended
monitoring. An operator connects the multiprobe to a computer equipped with a
communications software. Then, he lowers the multiprobe in the water and receives
measurements from the instrument. The data is displayed on the computer screen. The
multiprobe can be lowered to different locations along the sample area in order to study
the nature of the water based on several points of reference.