Glossary - Siemens Sitrans LR250 Operating Instructions Manual

Glossary

accuracy: degree of conformity of a measure to a standard or a true value.
agitator: mechanical apparatus for mixing or aerating. A device for creating turbulence.
algorithm: a prescribed set of well-defined rules or processes for the solution of a problem in a
finite number of steps.
ambient temperature: the temperature of the surrounding air that comes in contact with the
enclosure of the device.
antenna: an aerial which sends out and receives a signal in a specific direction. There are four
basic types of antenna in radar level measurement, horn, parabolic, rod, and waveguide.
attenuation: a term used to denote a decrease in signal magnitude in transmission from one
point to another. Attenuation may be expressed as a scalar ratio of the input magnitude to
the output magnitude or in decibels.
Auto False-Echo Suppression: a technique used to adjust the level of a TVT curve to avoid the
reading of false echoes. (See TVT.)
Auto False-Echo Suppression Distance: defines the endpoint of the TVT distance. (See TVT.)
This is used in conjunction with auto false echo suppression.
beam angle: the angle diametrically subtended by the one-half power limits (-3 dB) of the
microwave beam.
beam spreading: the divergence of a beam as it travels through a medium.
blanking: a blind zone extending away from the reference point plus any additional shield
length.The instrument is programmed to ignore this zone.
capacitance: the property of a system of conductors and dielectrics that permits the storage of
electricity when potential differences exist between the conductors. Its value is
expressed as the ratio of a quantity of electricity to a potential difference, and the unit is a
Farad.
confidence: see Echo Confidence
damping: term applied to the performance of an instrument to denote the manner in which the
measurement settles to its steady indication after a change in the value of the level.
dB (decibel): a unit used to measure the amplitude of signals.
derating: to decrease a rating suitable for normal conditions according to guidelines specified
for different conditions.
dielectric: a nonconductor of direct electric current.
1)
Many conductive liquids/electrolytes exhibit dielectric properties; the relative
dielectric constant of water is 80.
7ML19985JF04 SITRANS LR250 (PROFIBUS PA) – OPERATING INSTRUCTIONS
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