According to WELMEC's
Gravity Zone Concept for Weighing Instruments under
Legal Control manufacturers of g-dependent
weighing instruments may define acceptable places of use in the form of
a 3 dimensional zone. Thus, national regulations based on administrative
boundaries loose their meaning, nevertheless they remain valid.
The zone margins are declared first by a northern and southern latitude
and second by a lower and upper height above the sea level.
(see example: Paris).
The longitude of the designated place of use has no meaning, since
the associated mathematical model, the Normal Gravity Field,
is rotationally symmetric. The maximum acceptable extension of the
margins is fixed by a third of the
maximum permissible error.
The following program should ease the determination of gravity zones
concerning a specific weighing instrument type in consideration of
the aforementioned criterium. As the characteristics of the
individual instrument, first, the number of verification scale intervals
(n = Max/e)
and second, the factor of the maximum permissible error
(mpe/e)
have to be set. For the designated place of use approximations of the
latitude and the height are sufficient. By pressing
the margins will be computed in that way, that the occuring
gravity differences between the latitudes and heights are
equally distributed referring to the reference location.
The single margins can be changed with the
buttons
again in consideration of the error criterium.
(e.g. extented flat zones in lowlands)
