Fisher FERITSCOPE FMP30 - Additional Literature

Operator‘s Manual FERITSCOPE
®
FMP30 Page 223
Glossary
used to control the production process. This modern method of quality
control ensures constant good manufacturing quality, with a minimum
level of rejected parts. Normal distribution of the measurements is re-
quired so that statistical process control can be used for quality control
purposes.
Stop bit
With serial asynchronous data transfer, the stop bit is added to the data
word to be transferred. 1 to 2 bit logic Ones are used. After the stop
bit, the sender remains at logic One until the start bit of the next charac-
ter arrives.
Student factor t
Sum frequency
A form of display of the measurement data distribution, such that the
number of measurements smaller or equal to a particular measurement
is calculated and displayed in percent.
Sum frequency chart Probability chart (Gaussian probability paper, sum
frequency chart, probability paper)
Systematic measurement errors Measurement errors
System Check
A significant part of monitoring the test equipment. Calibration stan-
dards or, even better, reference samples, are used to check the calibra-
tion and to verify the stability of the instrument.
t
The student distribution factor t can be obtained from any popular pub-
lication of mathematical statistics tables (e.g., / 4 /) and is given as fol-
lows:
Example: At a confidence level of 95 % and N > 200 (resulting in a de-
gree of freedom f = 199 (because of f = N-1)), the student factor is
t
97.5;199
=1.96.
Test value E
Coefficient for the measurement accuracy/quality of the calibration
of the opened application file. This test value is calculated in the CAL-
t
1

2
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

f;