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By means of the statistic alarms management the system notifies if there are unu-
sual patterns or trends in C
ONTROL CHARTS, which could be evidence of wrong beha-
viour during the production.
The alarms refer to:
• Exceeding of C
ONTROL LIMITS
• RUNNING ALARM on XR/S chart (i.e. seven points in a row on one side of the middle
line between C
ONTROL LIMITS)
• T
REND ALARM on XR/S chart (i.e. seven points in a row that are consistently incre-
asing or decreasing)
• M
IDDLE THIRD ALARM on XR/S chart (i.e. normal distributions have generally about
2/3 of the points within the middle third of the region between the C
ONTROL LIMITS
and about 1/3 will be in the outer two/thirds of that region, if this does not hap-
pen there could be a problem on C
ONTROL LIMITS values).
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