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No. 99MBC071A
3.1.1.3 Measurement interval (measurement time)
A measurement interval (measurement time) varies depending on the averaging method and
the number of scans selected for the measurement data.
There are two types of averaging method: the arithmetical average and the moving average.
Select the one best suited for the user’s purpose.
1) Arithmetical average
• If a moving workpiece is measured, the diameter of the workpiece is determined by
averaging the measured data taken from each section (a: first measurement, b: second
measurement, .... n: nth measurement) of the workpiece the specified number of averaging
times, as shown below.
ban
. . .
second measurement
first measurement
nth measurement
Moving direction
Moving workpiece
• One of the following number of averaging times can be selected: 1, 2, 4, 8, ....1024, 2048.
• This is suitable for measuring a still object or the run-out of rollers, etc.
2) Moving average
In the moving average method, a measurement interval identical to that in the arithmetical
average is divided into finer sections such as a1 (1st measurement), a2 (2nd measurement), -
- - , an (nth measurement). Each measurement is performed almost in parallel. If, for ex-
ample, the number of averaging times is set to 512, the first measurement requires the
amount of time that corresponds to 512 scans. However, for the second measurement onward,
only the time for 16 scannings is required. With respect to a workpiece with a changing
diameter, this method provides data with smooth variation because of the many pieces of
data, and also quickly detects the trend of workpiece diameter variation.
. . .
. . .
Moving direction
Moving workpiece
Measurement with
arithmetical averaging
Measurement with
arithmetical averaging
an measurement
a1
a2
an
a1 measurement
a2 measurement
Output of an measurement
Output of a2 measurement
Output of a1 measurement
• One of the following number of scans can be selected: 32, 64, 128, ....1024, 2048.
• This method is suitable for the feedback control of wire drawing machines and extruding
machines.
