VEGA VEGAPULS 51K…54K Profibus PA - Manual (Page 41)

VEGAPULS 51P … 54P 41
24890-EN-041227
Set-up
Ampl.:
XX dB
S-N:
XX dB
5. Conditioning
Under the menu item " Conditioning“, you
select the product distance at 0 % and at 100
% filling. Then, you enter the parameter and
the physical unit as well as the decimal point.
Enter in the menu window " 0 % corresponds“
the numerical value of the 0 % filling. In the
example of the adjustment with the PC and
the adjustment software VVO, this would be
45 for 45 liters.
• Confirm with " OK“.
With the "—>“ key you switch to the 100 %
menu. Enter here the numerical value of your
parameter corresponding to a 100 % filling.
In the example 1200 for 1200 liters.
• Confirm with " OK“.
If necessary, set the decimal point. However,
note that only max. 4 digits can be displayed.
In the menu "
prop. to“ you choose the physi-
cal quantity (mass, volume, distance…) and
in the menu "
Unit“ the physical unit (kg, l, ft 3 ,
gal, m 3 …).
Linearisation:
A linear correlation between the percentage
value of the product distance and percent-
age value of the filling volume has been pre-
set. With the menu "Lin. curve“ you can
choose between linear, spherical tank and
cylindrical tank. The generation of a custom-
ized linearisation curve is only possible with
the PC and the adjustment program VVO.
6. Meas. conditions
(see menu schematic)
7. False echo memory
A false echo storage is always useful when
unavoidable false echo sources (e.g. struts)
must be minimised. By creating a false echo
memory, you authorise the sensor electronics
to record the false echoes and save them in
an internal database. The sensor electronics
treats these (false) echoes differently from
the useful echoes and filters them out.
8. Useful level, noise level
In the menu
you get important information on the signal
quality of the product echo. The greater 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 greater the "S-N“ value (difference be-
tween the amplitudes of the useful signal level
and the noise level), the better the measure-
ment:
> 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
This means that the noise level is only
68 dB – 53 dB = 15 dB.
A 15 dB noise level and a 53 dB signal differ-
ence yield a high degree of measurement
reliability.
9. Outputs
Under the menu "Outputs“ you determine, for
example, whether the current output should
be inverted, or which unit of measurement
Lin.
curve
Linear
Integra
tion
time
0 s
Adjust
ment Signal
condit
ioning
Scal
ing