BA_078_en_10.01 Level transmitter PASCAL Ci4 LEVEL
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emptying. When switching on the tank shape, the control points are sorted and adjusted in
such a way that a valid table is created with a reference to the level zero (see below).
Switching the tank shape on/off
The tank shape cannot be edited and used for the volume calculation at the same time. It
must be switched off before changing or teaching in the tank shape. The set alarm current
is then issued at the current output if the volume or weight is selected as the measurand.
The following steps are performed when switching on the tank shape:
Sorting control points in rising order according to height
Deleting closely spaced control points (height difference <0,1 mm)
Checking if the volume values are also arranged in rising order
Adjusting the volume values if necessary so that the compensating curve runs
through the 0 m / 0 m
3
point
Control points can be deleted and added very easily by means of automatic sorting. For
example, if a further control point is required to achive the necessary accuracy, this can
easily be added at the end of the table. This is shifted to the correct point in the control
point list when switching on the tank shape by means of a.m. automatic sorting.
If the same fill height is taught-in twice by mistake during the teach-in process, two control
points will be very close together, which can lead to problems with the volume calculation.
The odd control point is deleted after checking for closely located control points.
Checking the volume values avoids input errors. The table cannot be switched on if the
volume values are not also sorted in rising order after sorting the height values.
The level zero applies to all fill level variables. Consequently, the height value 0 m must
always correspond to the volume 0 m
3
(or in other units). This is ensured by adjusting the
volume values when switching on the table in such a way that the compensating curve
runs through 0/0.
Figure 21: Shifting the tank shape table
A taught-in table is converted into the necessary format automatically by sorting and ad-
justing. The following figure shows an example of the process.
A tank shape was taught-in with four control points by emptying the tank. The first control
point with a full tank (here 0 m
3
) is the reference point for additional volume figures. 2 m
3
were discharged before reaching the second control point. A further cubic metre was dis-
charged before reaching the third control point, i.e. 3 m
3
in total. The level zero corre-
sponds to the lower edge of the outlet. The flow meter indicates 3,6 m
3
after emptying the
tank. That is the volume value for the last control point.
The height values are sorted first when switching on the table. Then all volume values are
adjusted by 3,6 m
3
so that a fill height of zero corresponds to a volume of zero.
