Siemens SITRANS LG270 Operating Instructions Manual page 38

Linearisation A linearisation is necessary for all vessels in which the vessel volume
does not increase linearly with the level - e.g. a horizontal cylindri-
cal or spherical tank, when the indication or output of the volume is
required. Corresponding linearisation curves are preprogrammed
for these vessels. They represent the correlation between the level
percentage and vessel volume.
The linearisation applies to the measured value indication and the
current output. By activating the appropriate curve, the volume per-
centage of the vessel is displayed correctly. If the volume should not
be displayed in percent but e.g. in l or kg, a scaling can be also set in
the menu item "Display".
Warning:
If a linearisation curve is selected, the measuring signal is no longer
necessarily linear to the filling height. This must be considered by the
user especially when setting the switching point on the limit signal
transmitter.
In the following, you have to enter the values for your vessel, for
example the vessel height and the socket correction.
For non-linear vessel forms, enter the vessel height and the socket
correction.
For the vessel height, you have to enter the total height of the vessel.
For the socket correction you have to enter the height of the socket
above the upper edge of the vessel. If the socket is lower than the up-
per edge of the vessel, this value can also be negative.
Fig. 22: Vessel height and socket correction value
D Vessel height
+h Positive socket correction value
-h Negative socket correction value
38 SITRANS LG270 - Operating Instructions PBD-51041506