ISO 16063-21:2003/Amd 2:2024

International
Standard
ISO 16063-21
First edition
Methods for the calibration of
2003-08-15
vibration and shock transducers —
AMENDMENT 2
Part 21:
2024-11
Vibration calibration by comparison
to a reference transducer
AMENDMENT 2
Méthodes pour l'étalonnage des transducteurs de vibrations et
de chocs —
Partie 21: Étalonnage de vibrations par comparaison à un
transducteur de référence
AMENDEMENT 2
Reference number
ISO 16063-21:2003/Amd.2:2024(en) © ISO 2024

ISO 16063-21:2003/Amd.2:2024(en)
© ISO 2024
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ii
ISO 16063-21:2003/Amd.2:2024(en)
Foreword
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iii
ISO 16063-21:2003/Amd.2:2024(en)
Methods for the calibration of vibration and shock
transducers —
Part 21:
Vibration calibration by comparison to a reference
transducer
AMENDMENT 2
Introduction
Add the following paragraph at the end of the Introduction:
ISO 16063-21:2003/Amd 2 aims to explain better the use of reference transducers, different calibration set-
ups and opens up the frequency limits for the applicable calibration range.

1  Scope
Add the following sentence at the end of the scope before the NOTE:
"This document is applicable to calibrations outside the frequency range from 0,4 Hz to 10 kHz, considering
the additional facts described in 4.3. Systems have been demonstrated to cover the range from 0,01 Hz to
30 kHz."
4.3
Replace the last but one paragraph by the following:
"The reference transducer may be of the back-to-back type meant for direct mounting of the transducer to
be calibrated on top of it, in a back-to-back configuration, see Figure 1 a). It may also be a transducer used in
a fixture, see Figure 1 b), or underneath the exciter mounting platform (built-in reference transducer), see
Figure 1 c), always in line with the transducer to be calibrated. In the setup shown in Figure 1 c) the reference
might even be an integral part of the exciter (which means it cannot be detached). To reduce the influence
of rocking motions, the centres of the seismic elements of both transducers should be superimposed on one
axis coinciding with the axis of vibration. It is not recommended to mount the two transducers side by side
as rocking motions will often be present, causing large errors in many circumstances.
For low frequency calibrations requiring measurements below a few Hz, long stroke exciters are used giving
displacements of 100 mm or more. The setups are normally like the one shown schematically in Figure 2.
The principle is the same as Figure 1 b) but the armature is a sledge driven by an electromagnetic system
or otherwise. The sledge configuration permits heavy transducers to be calibrated. Some transducers (e.g.
seismometers) are sensitive in the transverse direction with respect to their mounting surface. They can
then be mounted directly on the sledge without the fixture 7 in Figure 2.
For these low frequency setups, the influence of rocking motion typically is very low, so side by side
measurements can be performed with low uncertainty.
...