Siemens Sitrans LR250, Руководство по эксплуатации, Страница: 294 / 306

Glossary
SITRANS LR250 (PROFIBUS PA)
292
Operating Instructions, 08/2014, A5E32221386-AC
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
device 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 a device 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. Many conductive liquids/electrolytes exhibit dielectric
properties; the relative dielectric constant of water is 80.