Notes On Log Data; Error Outputs; Dispersion (Standard Deviation); Evaluation Of Measuring Points - HEIDENHAIN ITNC 530 - CYCLE PROGRAMMING User Manual

Notes on log data

Error outputs

In the Test mode (Q406=0) the TNC outputs the accuracy that can be
attained by optimization and/or the accuracies attained through
optimization (Modes 1 and 2).
If the angular position of a rotary axis was calculated, the measured
data is also shown in the log.

Dispersion (standard deviation)

In the log, 'dispersion', a term from statistics, is used as a measure
of accuracy. Measured dispersion (measured standard deviation)
means that 68.3% of the actually measured spatial errors are within
the specified range (+/–). Optimized dispersion (optimized
standard deviation) means that 68.3% of the spatial errors to be
expected after the correction of the kinematics are within the
specified range (+/–).

Evaluation of measuring points

The valuation numbers are a measure of the quality of the
measuring positions with respect to the changeable transformations
of the kinematics model. The higher the valuation number, the
greater the benefit from optimization by the TNC.
Because the TNC always needs two transformations for measuring
the position of a rotary axis, two valuation numbers per rotary axis
are determined. If a complete valuation is missing, the position of a
rotary axis in the kinematics model is not completely defined. The
higher the valuation number, the greater the benefit from changing
the deviations of the measuring points by adjusting the
transformation. The valuation numbers are independent of the
measured errors. They are defined by the kinematics model, the
position and the number of measuring points per rotary axis.
The valuation of any rotary axis should not fall below a value of 2
Values greater or equal to 4 are desirable.
If the valuation numbers are too small, increase the
measurement range of the rotary axis, or also the number
of measuring points. If these measures do not improve the
valuation number it may be because of an incorrect
kinematic description. If necessary, inform your service
agency.
480 Touch Probe Cycles: Automatic Kinematics Measurement