Uncertainty Management in the measurements performed by means of virtual instruments

The uncertainty management is the discipline of optimising the cost of a measurement versus the uncertainty target. In particular, the paper deals with the measurements performed by using a generic virtual instrument. The task is achieved by using the PUMA (procedure for uncertainty management) method that is an iterative technique originally conceived for geometrical and mechanical measurements. The approach is completely based on the "guide to the expression of uncertainty in measurement" rules, but provides a more engineering methodology, since it allows to optimize the cost of the measurements versus the uncertainty target, avoiding the use of inadequate or, on the contrary, too expensive resources for the uncertainty estimation. According to the PUMA method, four different approaches to evaluate the uncertainties are presented and they are applied starting from the coarser, but quicker and cheaper one and keeping on with the more precise methodologies. In the practical cases, it is very probable to prove that the first iteration of the PUMA method is enough to optimise the uncertainty budget.