VEGA VEGAPULS 56 Profibus PA - Manual (Page 58)

58 VEGAPULS 56 Profibus PA
Setup
The user programmable linearisation curve is
generated by index markers. Each index
marker consists of a value pair. A value pair
is generated from a value "
Linearised“ and a
value " Percentage value“. “Percentage value”
represents the distance as a percentage of
the level. "
Linearised“ represents the per-
centage of vessel volume at a certain per-
centage value of level.
In the field " Transfer measured value“ the
current level as a percentage of the adjusted
span is displayed. The measuring window
has already been adjusted with the min./max.
adjustment. In the example, the span is
4.58 m and is between 5.85 m (empty) and
1.27 m (full), see the following illustration.
5.85 m meas. distance correspond to 0 %
level. 1.27 m meas. distance correspond to
100 % level. The span is therefore 4.58 m
(5.85 m – 1.27 m = 4.58 m).
A percentage value of 95.79 % then means
that 4.387 m of the adjusted span (4.58 m)
have been reached:
4.58 • 0.9579 = 4.387 m.
The distance (product distance) outputted
by the sensor, if you have chosen "
Distance“,
is then:
5.85 – (4.58 • 0.9579) = 1.463 m.
If the index markers or value pairs of your
vessel are not known, you must gauge the
vessel incrementally or calculate it with the
vessel calculation program of VVO.
Defining the linearisation curve by incre-
mental filling
In the characteristics of the example, you see
four index markers or value pairs. There is
always a linear interpolation between the
index markers. The example vessel consists
of three cylindrical segments of different
height and diameter. The middle segment
has a considerably smaller diameter.
• Click in the check box " Show scaled val- Show scaled val- Show scaled val- Show scaled val- Show scaled val-
ues ues ues ues ues“, to have the selected unit of measure-
ment displayed on the y-axis (left bottom
part in the menu window).
0 m
100 % at 1.27 m
1.463 m (95.79 %)
Span
4.58 m
(100 %)
4.387 m
(95.79 %)
0 % at 5.85 m