Glossary
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MMS
®
Inspection DPM High
distribution may indicate systematic errors during the measurement. The rep-
resentation is based on the entire batch.
Measured reading
Display value determined by the measuring instrument
Measurement uncertainty
Specification on the calibration standard. The assumed "true" value (μ) of the
quantity being measured is in an interval around the measured mean value
(Nominal value) of a series of measurements with a certain probability (k=2:
95 %). The limits of this interval have the distance of the measurement uncer-
tainty U from the mean value (nominal value),
nominal value - U ≤ μ ≤ nominal value + U.
Measuring application
A measuring application is determined by customer requirements and by stan-
dards. According to these requirements, the measurement settings are stored
in the gage in a batch. If any one of these parameters changes, there is a new
measuring application and you have to create a new Batch.
Precision
Unlike trueness, precision is a gage property. It can be characterized very eas-
ily, e.g. by repeated measurements on a test piece (the true measurand of
which does not need to be known) in one and the same position under repeat-
ability conditions. The mean value gives the desired measured reading; the
standard deviation of the measurement series is a measure of the gage's pre-
cision. If the measuring application is correctly calibrated, the mean value for
the measurement series will also be correct (Trueness) and match the true val-
ue within the Measurement uncertainty.
Repeatability
Repeatability characterizes the random deviations in the results obtained with
one gage, by one person, with one and the same test piece at the same mea-
suring position from repeated measurements, i.e. under repeatability condi-
tions.
Measuring repeatedly under constant conditions at the same measurement lo-
cation results in random deviations of the measured readings. Consistent con-
ditions means: Measurements according to a defined procedure on the same
test piece, at short intervals, with the same measuring instrument, by the same
person at the same place. The standard deviation of measured readings ac-
quired under repeatability conditions is a measure of the repeatability.
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