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No. 99MBC095A
3.2.10 Abnormal data elimination
• The abnormal data elimination function eliminates measurements that are very different
from those specified for the machined workpiece, from the measurement data (neither the
measurement is displayed nor is data output performed).
If, for example, the grindstone of a centerless grinder is controlled based on the measured
data from the LSM, it is possible that a large measurement error may be created due to the
coolant used with the workpiece.
As shown in the figure below where foreign matter (with a height of h) adheres to within
the averaging region L of the workpiece (with a diameter of D). An abnormal outside
diameter results in the region of l and the displayed measurement will be (D + lh / L). As
the result the grinder is subject to improper control that involves some error.
h
D Workpiece
l
L
Workpiece feed direction
Because the use of this function can eliminate abnormal measurement data generated due
to the adhered foreign matter, the grindstone can be controlled and fed properly.
• Judgment of valid data or abnormal data will be performed at each measurement interval.
Valid data includes those satisfy the following relation: Lower abnormal limit ≤ (Measure-
ment) < Upper abnormal limit. All other data will be discarded as abnormal data.
• The following table shows the relationship between measurements and upper and lower
abnormal limits.
etanimiletonoD/etanimilE
rewoldnareppuehthtobfidegduJ(tnemerusaeM
).teserastimillamronba
etanimilEtimillamronbarewoL<tnemerusaeM
etanimiletonoD
)tnemerusaemasadetpecca(
timillamronbarewoL ≤ reppU<tnemerusaeM
timillamronba
etanimilEtnemerusaeM ≥ timillamronbareppU
• In the basic setup select whether this abnormal data elimination function should be used. If
it is the setting of (lower abnormal limit, upper abnormal limit, and count value) should be
performed before actual tolerance judgment.
This count value indicates the number of pieces of abnormal data that occurred until the
alarm will be issued. This alarm output will be sent to the optional Second Analog I/O
Interface by CNT form (The alarm will not be issued if the count value is set to zero).
• Abnormal data elimination function effects in single-run and continuous-run measure-
ments.
• If “Err-0” (specified workpiece not present) is displayed in the sample measurement, the
valid data collected will be discarded.
NOTE If a long series of abnormal data appears, measurement can no longer be continued
since most of the measured data must be eliminated. To avoid this problem, always
monitor CNT output.
