Page 19 - 4150

hire a “lowborn” multimeter. On the contrary, you use instruments
which are well-known and well-regarded, which come with
documents and certificates, so as to be sure of their traceability and,
therefore, to better guarantee the quality of the measurements. These
instruments (said to be “reference instruments”) have to be acquired
after you have seriously studied the criteria of choice. It is known that:
– the ideal instrument does not exist;
– the instrument closest to what is ideal is too expensive;
– each buyer limits the claims of technical applicants.
Moreover, the choice of an instrument depends on its type of use.
Four types of utilization can be distinguished:
– for a study (you must look for an instrument that can evolve);
– for a site (robustness ought to be favored);
– in manufacturing (the “cost” factor will probably prevail);
- for a laboratory (your preference will go to a very reliable,
strong and proven instrument).
Analysis of what is already available
The first thing to do will be to see if there is not already in the
firm some available material which can meet your needs. This
requires:
– good communication between the various parties concerned
with the measurements; and – a good knowledge of the material
available. The latter point is all the more important when there is a
risk of technological obsolescence (using a state-of-the-art instrument
to its maximum capacity justifies its acquisition and it makes it easier
to get new ones), or when the material is very expensive (when you
increase the duration of its productive use, you make its amortization
easier).
Assessment and acquisition of material
Speaking of compromise about the choice was actually slightly
simplistic. Of course, the economic requirements are obviously taken
into account; few are the cases when the material is selected without
the price being considered (either before or after the purchase!). As for
the assessments which are otherwise made, they quite simply depend
on the competence and professionalism of the person in charge of the
metrological function. He must indeed be on a permanent
technological watch.
17