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Mahr GmbH • Millimar C1202
3.2.2 Master
Measurements performed with just one transducer are generally comparative
measurements, i.e. the deviations from a nominal value are measured and displayed. These
nominal values are determined using measurements on gage blocks, setting plugs or special
workpieces with known dimensions, known as
"
master workpieces
"
or
"
masters
"
for short.
These master measurements are performed before beginning the actual measurement.
There are one point and two point master measurements.
See Section 5.1.5., Setup 1, Number of masters for setting one-point and two-point master
measurements
3.2.2.1 One-point master measurement
Only one master (gage block) is contacted in a one-point master measurement, and
the displayed value is compared with the entered nominal value. This determines if the
actual value just measured deviates from the nominal value and if so, by how much. It is
assumed that the deviation determined here is constant across the entire measuring range
and corrects the raw values of the subsequent workpiece measurements by the amount
determined here before the measuring results are displayed. If the actual value displayed is
+ 10µm greater than the nominal value of the master, the raw values of all of the subsequent
workpiece measurements are reduced by 10µm and the corrected value is displayed as
the measuring result. The characteristic curve of the probe is thus shifted accordingly
(in parallel) in the display range.
