Siemens Sitrans LR250, Руководство по эксплуатации, Страница: 297 / 306

Glossary
SITRANS LR250 (PROFIBUS PA)
Operating Instructions, 08/2014, A5E32221386-AC
295
polarization error
the error arising from the transmission or reception of an electromagnetic wave having a
polarization other than that intended for the system.
PROFIBUS PA
one of the PROFIBUS family of protocols, specifically tailored for the needs of process industries
(PA = Process Automation).
propagation factor (pf)
where the maximum velocity is 1.0, pf is a value that represents a reduction in propagation
velocity as a result of the wave travelling through a pipe or
medium.
pulse radar
a radar type that directly measures distance using short microwave pulses. Distance is
determined by the return transit time.
radar
radar is an acronym for RAdio Detection And Ranging. A device that radiates electromagnetic
waves and utilizes the reflection of such waves from distant objects to determine their existence
or position.
range
distance between a transmitter and a target.
range extension
the distance below the zero percent or empty point in a vessel.
relative permittivity
see dielectric constant.
repeatability
the closeness of agreement among repeated measurements of the same variable under the
same conditions.