Glossary - Siemens SITRANS LUT400 Series Operating Instructions Manual

Glossary

accuracy: degree of conformity of a measure to a standard or a true value.
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.
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 Range: defines the endpoint of the TVT distance. (See TVT.) This
is used in conjunction with auto false echo suppression.
blanking: a blind zone extending away from the reference point plus any additional shield
length.The device is programmed to ignore this zone.
confidence: describes the quality of an echo. HIgher values represent higher quality.
Confidence threshold defines the minimum value.
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.
echo: a signal that has been reflected with sufficient magnitude and delay to be perceived in
some manner as a signal distinct from that directly transmitted. Echoes are frequently
measured in decibels relative to the directly transmitted signal.
echo confidence: the recognition of the validity of the echo. A measure of echo reliability.
echo lock window: a window centered on an echo in order to locate and display the echo's
position and true reading. Echoes outside the window are not immediately processed.
Echo marker: a marker that points to the processed echo.
Echo Processing: the process by which the device determines echoes.
Echo Strength: describes the strength of the selected echo in dB referred to 1 μV rms.
Echo Profile: a graphical display of a processed echo.
false echo: any echo which is not the echo from the desired target. Generally, false echoes are
created by vessel obstructions.
far range: the distance below the zero percent or empty point in a vessel.
figure of merit: combines noise level, tracking quality, and signal strength to measure the
quality of the reported echo value.
A5E33329501 SITRANS LUT400 (HART) – OPERATING INSTRUCTIONS Page 283