NIVELCO MicroTREK HB, Руководство пользователя и программирования, Страница: 58 / 68

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5.4.2. Gain and voltage amplitude
As explained amongst the measuring principles in the introduction, the level of a medium is converted from a return signal (the medium reflection) received by the
gauge: this signal takes a certain amount of time to return to get to the gauge and it has a certain strength / size measured in milli-volts (dependant on the dielectric
constant

r
of the medium).
All pulse signals returning to the gauge electronics block (including flange, obstruction and the medium surface reflections) are converted to voltage amplitudes.
The gauge’s microprocessor looks for the largest signal that is over a set voltage amplitude, called the “threshold”, and identifies this as the medium being measured.
In order for the signal is applicable by the gauge, the microprocessor will amplify the signal by increasing gain. Once the signal is within a set “working” range, the
gauge follows this signal. The gauge registers any changes of the signal returned to the converter and translate it into a displayed level or volume.
The rate of the Gain is depending on the function of voltage amplitude.
This defines the default threshold value when the gauge is searching for the medium level.
A strong return signal sets low gain rate (i.e. Gain 0 or a small amplification).
However, if the signal is very weak, then a Gain of 3 (i.e. high signal amplification) is given.
Example of signal amplification: