KERN KXG-TM Etriebs- Und Installationsanleitung Seite 134

Switch between number of items and weight
With the UNIT key you can switch between number of items and weight:
By switching the scale off and then on again the scale starts in the unit
counting mode. The current reference weight remains stored until the
reference is set again or the power supply is interrupted.
The counting function is not active, if the weight is under 20d or if below
the minimum piece weight (< 0.2 D) is reached.
Automatic reference optimization
In order to improve the counting exactness, the reference can be optimised by
adding more pieces. At every reference optimisation, the reference weight is
calculated anew. As the additional pieces increase the base for the calculation, the
reference also becomes more exact.
 If the number of placed parts are 5 pieces more than the reference, then the
automatic reference optimisation starts. The reference weight is calculated anew.
22 KXS/KXG-TM-BA_IA-e-1621