Averaging - Siemens SINUMERIK 840 User Manual

08.96
1.6.2

Averaging

Averaging in combination with higher-order measurement weighting has proved a suitable
means to do this.
The formula of the average-value generation chosen is:
Av = Av –
new old
Av = Average value new = amount of correction
new
Av = Average value of last measurement
old
k = Weighting factor for calculating the average value (R29)
D = Set/actual difference measured (minus empirical value, if any)
i
This formula takes into account the trend of the dimensional deviations of a series of
machining operations. The weighting factor k (R29), on the basis of which the average value is
generated, can be chosen.
A new measurement result affected by random dimensional deviations, as mentioned above,
only influences the new tool offset to some extent, depending on the weighting factor.
D
i
Average values
calculated
Setpoint
(R42)
0 1
Fig. 1.19 Computational variation of the average value with different weightings k
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Siemens AG 1990 All Rights Reserved
SINUMERIK 840/850/880 (BN)
Av – D
old i
k
k=1
k=2
Average value
calculated
k=3
k=10
2 3 4 5
Number of averaging operations (workpieces)
6FC5197- AB70
1.6.2 Averaging
Set/actual difference
Lower limit (R33) = "Zero offset"
6
1 Introduction
1–21