Legal weighing uses the verification interval e, not the displayed division d. Confusing the two is the most common reason a scale fails approval despite working well.
Definitions
e is the value, in mass units, of the smallest interval that the approval is based on. d is what the display shows. For an approved instrument e is usually equal to d, but a scale may display finer than e as long as the indication is within the rounding rules. The maximum permissible error is expressed in terms of e, typically 0.5 e at low load, 1.0 e at medium load and 1.5 e at high load.
Why the ratio matters
If the display shows d = e/5, the extra digits invite readings that the approval does not support. Some jurisdictions prohibit this; others allow it with a note. Check the local requirement before configuring a finer display to please an operator.
Consequences for the cell
The number of verification intervals n = Max/e sets the required accuracy class. A 3000 division scale needs a C3 cell; a 6000 division scale needs C6 or better, and also a better mechanical installation. Increasing the displayed resolution without changing the cell only moves the error into the display.
Kevin Huang