Vega WEIGHTRAC 31 Operating Instructions Manual page 50

7 Setup with PACTware
Adjustment/Linearization
(DTM)
50
If you exchange the belt, you have to carry out the zero rate determi-
nation again.
In this menu item you can carry out the adjustment of the sensor.
During linearization, a corresponding total weight of conveyed mate-
rial is assigned to a particular pulse rate.
It is therefore important to detect the weight of the conveyed material
correctly. This means that you have to use a precise, possibly also
calibrated, scale.
Make sure that no material is lost from the belt or the transport and
that no foreign material is added. If you carry out the measurement
with a truck, make sure that you have comparable measuring condi-
tions (always measure with or without driver, use the same vehicle or
compensate for differences, make sure there is no residue buildup on
the loading platform of the vehicle, etc.).
Make sure that the density of the material during the linearization cor-
responds to the original material measured later on.
Fig. 35: Add adjustment points
Due to the measuring principle, there is no linear relationship between
pulse rate and level. Hence, this adjustment (i.e. linearisation) must in
any case be carried out.
For very precise measuring results, you should carry out this adjust-
ment with different filling heights (flow rates) on the conveyor belt. The
bigger the difference in flow rates, the more precise the linearization.
The way you measure the total quantity of the conveyed material
depends on the options you have on site.
You can collect the total quantity of conveyed material on a truck and
determine the weight with a truck scale. But you can also weigh the
material before the measurement and keep it ready for the lineariza-
tion. Another possibility would be to transfer the conveyed material to
a container sitting on load cells.
You can carry out the linearization with two different principles:
•
Dynamically - with running conveyor belt
•
Statically - with stationary conveyor belt
WEIGHTRAC 31 • 4 ... 20 mA/HART - four-wire