Technical Reference; Principles Of Operation; Process Variables; Transmit Pulse - Siemens SITRANS LUT400 Operating Instructions Manual

Technical reference

A.1

Principles of Operation

The SITRANS LUT400 is a high quality ultrasonic controller, configured to meet the needs of
different applications, from medium range solids applications to liquids management with
open channel measurement capability. The LUT400 features our next generation of Sonic
Intelligence® advanced echo-processing software for increased reading reliability.
Note
Where a number precedes a parameter name (for example, Narrow Echo Filter (2.12.2.4.)
(Page 221)) this is the parameter access number via the local display. See Parameter
reference (LUI) (Page 167) for a complete list of parameters.
A.1.1

Process Variables

The Primary Variable (PV) is one of six process variables, and is set in Current Output
Function (2.5.1.) (Page 176).
● Level (difference between material level and Low Calibration Point),
● Space (difference between material level and High Calibration Point),
● Distance (difference between material level and sensor reference point),
● Head (difference between liquid level and Zero Head),
● Volume (volume of material based on level),
● Flow (flowrate in an open channel, based on head).
A.1.2

Transmit Pulse

The transmit pulse consists of one or more electrical "shot" pulses, which are supplied to the
transducer connected to the SITRANS LUT400 terminals. The transducer fires an acoustic
"shot" for each electrical pulse supplied. After each shot is fired, sufficient time is provided for
echo (shot reflection) reception before the next (if applicable) shot is fired. After all shots of
the transmit pulse are fired, the resultant echoes are processed. The transmit pulse
frequency, duration, delay, and associated measurement range are defined by parameters in
the Setup menu (see Setup (2.) (Page 168))
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Operating Instructions, 07/2019, A5E33329501-AC
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SITRANS LUT400