User's Manual

Table Of Contents
Glossary
SITRANS LR250 (HART)
Operating Instructions, 01/2014, A5E32220602-AB
257
polarization
the property of a radiated electromagnetic wave describing the time-varying direction and
amplitude of the electric field vector.
polarization error
the error arising from the transmission or reception of an electromagnetic wave having a
polarization other than that intended for the system.
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
RA
dio
D
etection
A
nd
R
anging. 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 humidity
the ratio of the actual amount of moisture in the atmosphere to the maximum amount of moisture
the atmosphere could hold (which varies depending on the air temperature).
relative permittivity
see dielectric constant.