User's Manual

Table Of Contents
Glossary
SITRANS LR250 (PROFIBUS PA)
260 Operating Instructions, 01/2014, A5E32221386-AB
shot
one transmit pulse or measurement.
speed of light
the speed of electromagnetic waves (including microwave and light) in free space. Light speed is
a constant 299, 792, 458 meters per second.
stilling-well
see stillpipe.
stillpipe
a pipe that is mounted inside a vessel parallel to the vessel wall, and is open to the vessel at the
bottom.
TVT (Time Varying Threshold)
a time-varying curve that determines the threshold level above which echoes are determined to
be valid.
two wire radar
a low-energy radar. Can be loop powered, analog, intrinsically safe 4 to 20 mA, or a digital
(BUS) transmitter.
waveguide antenna
a hollow, metallic tube that transmits a microwave signal to the product target.