VEGA VEGASON 51K…53K - Manual (Page 43)

VEGASON 51K … 53K 43
Set-up
Ampl.:
XX dB
S-N:
XX dB
4. Operating range
Without special adjustment, the operating
range corresponds to the measuring range.
The measuring range has already been ad-
justed with the min./max. adjustment. Gener-
ally it is useful to choose a slightly bigger
(approx. 5 %) operating range than the
measuring range.
Example:
Set min./max. adjustment to: 0,300 … 5,850
m; operating range to approx. 0,250 … 6,000
m.
5. Meas. conditions
(see menu plan no. 5)
6. Measurement in gases
Adjustment is only necessary when the
measurement is made in gases (Co
2
, He,
etc.) deviating from air. In case of measure-
ment in gases sound the distance of the
sensor to the product surface and enter in
the menu point "Measurement in gases“. The
sensor can then consider the modified sound
velocity in gases as opposed to air and pro-
vide correct levels.
7. False echo storage
A false echo storage is always useful when
false echo sources such as struts must be
reduced. With the creating of a false echo
storage, you authorise the sensor electronics
to note the false echoes and save them in an
internal database. The sensor electronics
treat these (false) echoes differently from the
useful echo and gates them out.
8. Useful and noise level
In the menu
you get important information on the signal
quality of the level echo. The higher the
"S-N“-value, the more reliable the measure-
ment (menu plan MINICOM).
Ampl.: Means amplitude of the level echo in
dB (useful level)
S-N: Means Signal-Noise, i.e. the useful
level minus the level of the back-
ground noise
The higher the "S-N“-value (distance of the
amplitude useful level to noise level), the
better the measurement:
> 50 dB
Measurement excellent
40 … 50 dB Measurement very good
20 … 40 dB Measurement good
10 … 20 dB Measurement satisfactory
5 … 10 dB Measurement sufficient
< 5 dB Measurement poor
Example:
Ampl. = 68 dB
S-N = 53 dB
68 dB – 53 dB = 15 dB
53 dB signal distance means very good
reliability.
This means that the noise level is only
68 dB – 53 dB = 15 dB.