SIST EN ISO 15548-1:2014
(Main)Non-destructive testing - Equipment for eddy current examination - Part 1: Instrument characteristics and verification (ISO 15548-1:2013)
Non-destructive testing - Equipment for eddy current examination - Part 1: Instrument characteristics and verification (ISO 15548-1:2013)
ISO 15548 identifies the functional characteristics of a general-purpose eddy current instrument and provides methods for their measurement and verification. The evaluation of these characteristics permits a well-defined description and comparability of eddy current equipment. By careful choice of the characteristics, a consistent and effective eddy current examination system can be designed for a specific application. Where accessories are used, these are characterised using the principles of this part of ISO 15548. This part of ISO 15548 gives neither the extent of verification nor acceptance criteria for the characteristics. They are given in the application documents.
Zerstörungsfreie Prüfung - Technische Ausrüstung für die Wirbelstromprüfung - Teil 1: Kenngrößen von Prüfgeräten und deren Verifizierung (ISO 15548-1:2013)
Dieser Teil von ISO 15548 legt die Funktionskenngrößen von Wirbelstromprüfgeräten für die allgemeine Anwendung fest und enthält Verfahren für deren Messung und Verifizierung.
Die Beurteilung dieser Kenngrößen ermöglicht eine genaue Beschreibung und Vergleichbarkeit von Wirbel-stromprüfeinrichtungen.
Durch sorgfältige Auswahl der Kenngrößen kann ein reproduzierbares und effektives Wirbelstromprüfsystem für spezifische Anwendungen entworfen werden.
Bei der Verwendung von Zubehörteilen sollten diese nach den Grundsätzen dieses Teils von ISO 15548 charakterisiert werden.
Dieser Teil von ISO 15548 enthält weder Vorschriften für den Umfang der Verifizierung noch für die Annahmekriterien der Kenngrößen. Diese sind in den Anwendungsdokumenten enthalten.
Essais non destructifs - Appareillage pour examen par courants de Foucault - Partie 1: Caractéristiques de l'appareil et vérifications (ISO 15548-1:2013)
L'ISO 15548-1:2013 identifie les caractéristiques fonctionnelles d'un appareil à courants de Foucault à usage général et fournit des méthodes pour les mesurer et les vérifier.
L'évaluation de ces caractéristiques permet de donner une description bien définie de l'appareillage à courants de Foucault et d'assurer la comparabilité entre appareillages.
Un système d'examen par courants de Foucault, cohérent et efficace, peut être conçu en choisissant méticuleusement les caractéristiques pour une application spécifique.
Lorsque des accessoires sont mis en oeuvre, ils sont caractérisés en appliquant les principes de l'ISO 15548-1:2013.
L'ISO 15548-1:2013 ne donne ni l'étendue de la vérification ni les critères d'acceptation des caractéristiques. Celles-ci sont définies dans les documents d'application.
Neporušitvene preiskave - Oprema za preiskave z vrtinčnimi tokovi - 1. del: Značilnosti aparatov in preverjanje (ISO 15548-1:2013)
Standard ISO 15548 določa funkcijske značilnosti instrumentov za preiskave z vrtinčnimi tokovi za splošno uporabo in navaja metode za merjenje in preverjanje s temi instrumenti. Ocena teh značilnosti omogoča dobro opredeljen opis in primerjavo opreme za preiskave z vrtinčnimi tokovi. S skrbno izbiro značilnosti se lahko oblikuje dosleden in učinkovit preiskovalni sistem za opremo za preiskave z vrtinčnimi tokovi za določeno uporabo. Če je uporabljen pribor, je ta opisan po načelih tega dela standarda ISO 15548. Ta del standarda ISO 15548 ne določa obsega preverjanja, niti kriterijev sprejemljivosti za lastnosti. Ti so podani v dokumentu, ki obravnava uporabo.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 15548-1:2014
01-julij-2014
1DGRPHãþD
SIST EN ISO 15548-1:2009
SIST EN ISO 15548-1:2009/AC:2010
1HSRUXãLWYHQHSUHLVNDYH2SUHPD]DSUHLVNDYH]YUWLQþQLPLWRNRYLGHO
=QDþLOQRVWLDSDUDWRYLQSUHYHUMDQMH ,62
Non-destructive testing - Equipment for eddy current examination - Part 1: Instrument
characteristics and verification (ISO 15548-1:2013)
Zerstörungsfreie Prüfung - Technische Ausrüstung für die Wirbelstromprüfung - Teil 1:
Kenngrößen von Prüfgeräten und deren Verifizierung (ISO 15548-1:2013)
Essais non destructifs - Appareillage pour examen par courants de Foucault - Partie 1:
Caractéristiques de l'appareil et vérifications (ISO 15548-1:2013)
Ta slovenski standard je istoveten z: EN ISO 15548-1:2013
ICS:
19.100 Neporušitveno preskušanje Non-destructive testing
SIST EN ISO 15548-1:2014 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 15548-1:2014
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SIST EN ISO 15548-1:2014
EUROPEAN STANDARD
EN ISO 15548-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2013
ICS 19.100 Supersedes EN ISO 15548-1:2008
English Version
Non-destructive testing - Equipment for eddy current
examination - Part 1: Instrument characteristics and verification
(ISO 15548-1:2013)
Essais non destructifs - Appareillage pour examen par Zerstörungsfreie Prüfung - Technische Ausrüstung für die
courants de Foucault - Partie 1: Caractéristiques de Wirbelstromprüfung - Teil 1: Kenngrößen von Prüfgeräten
l'appareil et vérifications (ISO 15548-1:2013) und deren Verifizierung (ISO 15548-1:2013)
This European Standard was approved by CEN on 11 November 2013.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same
status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2013 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 15548-1:2013 E
worldwide for CEN national Members.
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SIST EN ISO 15548-1:2014
EN ISO 15548-1:2013 (E)
Contents page
Foreword .3
2
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SIST EN ISO 15548-1:2014
EN ISO 15548-1:2013 (E)
Foreword
This document (EN ISO 15548-1:2013) has been prepared by Technical Committee ISO/TC 135 “Non-
destructive testing” in collaboration with Technical Committee CEN/TC 138 “Non-destructive testing” the
secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by June 2014, and conflicting national standards shall be withdrawn at
the latest by June 2014.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 15548-1:2008.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 15548-1:2013 has been approved by CEN as EN ISO 15548-1:2013 without any modification.
3
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SIST EN ISO 15548-1:2014
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SIST EN ISO 15548-1:2014
INTERNATIONAL ISO
STANDARD 15548-1
Second edition
2013-12-01
Non-destructive testing — Equipment
for eddy current examination —
Part 1:
Instrument characteristics and
verification
Essais non destructifs — Appareillage pour examen par courants
de Foucault —
Partie 1: Caractéristiques de l’appareil et vérifications
Reference number
ISO 15548-1:2013(E)
©
ISO 2013
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SIST EN ISO 15548-1:2014
ISO 15548-1:2013(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2013
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2013 – All rights reserved
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SIST EN ISO 15548-1:2014
ISO 15548-1:2013(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Eddy current instrument characteristics . 1
4.1 General characteristics . 1
4.2 Electrical characteristics . 2
5 Verification . 7
5.1 General . 7
5.2 Levels of verification . 7
5.3 Verification procedure . 8
5.4 Corrective actions . 8
6 Measurement of electrical characteristics of instrument . 8
6.1 Measuring requirements . 8
6.2 Generator unit . 9
6.3 Input stage characteristics .12
6.4 Signal processing.14
6.5 Output .23
6.6 Digitisation .23
Annex A (informative) Principle of frequency beat method .24
Annex B (informative) Method of measurement of linearity range between output and input .26
Annex C (normative) Alternative measurement of the input impedance .27
© ISO 2013 – All rights reserved iii
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SIST EN ISO 15548-1:2014
ISO 15548-1:2013(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2. www.iso.org/directives
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any
patent rights identified during the development of the document will be in the Introduction and/or on
the ISO list of patent declarations received. www.iso.org/patents
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
The committee responsible for this document is ISO/TC 135, Non-destructive Testing, Subcommittee
SC 4, Eddy current methods.
This second edition cancels and replaces the first edition (ISO 15548-1:2008), of which it constitutes a
minor revision. It also incorporates the Correction ISO 15548-1:2008/Cor 1:2010.
ISO 15548 consists of the following parts, under the general title Non-destructive testing — Equipment
for eddy current examination:
— Part 1: Instrument characteristics and verification
— Part 2: Probe characteristics and verification
— Part 3: System characteristics and verification
iv © ISO 2013 – All rights reserved
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SIST EN ISO 15548-1:2014
INTERNATIONAL STANDARD ISO 15548-1:2013(E)
Non-destructive testing — Equipment for eddy current
examination —
Part 1:
Instrument characteristics and verification
1 Scope
This part of ISO 15548 identifies the functional characteristics of a general-purpose eddy current
instrument and provides methods for their measurement and verification.
The evaluation of these characteristics permits a well-defined description and comparability of eddy
current equipment.
By careful choice of the characteristics, a consistent and effective eddy current examination system can
be designed for a specific application.
Where accessories are used, these are characterised using the principles of this part of ISO 15548.
This part of ISO 15548 gives neither the extent of verification nor acceptance criteria for the
characteristics. They are given in the application documents.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 12718, Non-destructive testing — Eddy current testing — Vocabulary
ISO 15549, Non-destructive testing — Eddy current testing — General principles
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 12718 apply.
4 Eddy current instrument characteristics
4.1 General characteristics
4.1.1 Type of instrument
a) An instrument has a general-purpose application when the relationship between the measured
quantity and the display or output is established by the user. A range of probes can be connected
to the instrument. The instrument manufacturer shall provide details of the internal electrical
characteristics, in order that the user can design the examination system. The examination system
shall be in accordance with ISO 15549. The user shall be able to vary the value of frequency, gain,
balance (unless an automatic balance is used), phase, filters and gain and zero of the display.
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SIST EN ISO 15548-1:2014
ISO 15548-1:2013(E)
b) An instrument is of specific application when the relationship between the measured quantity and
the display or output is explicitly defined in the range of application. The probe is specific to the
instrument. For this type of instrument, this part of ISO 15548 may be partially applied.
4.1.2 Power supply
The instrument can be powered by batteries or by the local AC power supply. The nominal values of voltage,
frequency and power consumption shall be stated, together with the tolerance for correct operation.
4.1.3 Safety
The instrument and its accessories shall meet the applicable safety regulations, for example, electrical
hazard, surface temperature, explosion, etc.
4.1.4 Technology
The instrument can be wholly analogue or partly analogue and partly digital.
The excitation can be single frequency, multifrequency, swept frequency or pulsed.
The instrument can be single or multichannel.
The instrument settings can be manual, remote controlled, stored or preset.
The instrument shall have component outputs and can be with or without a self-contained display.
4.1.5 Physical presentation
The instrument can be portable, cased or rack mounted, with the component parts integrated or modular.
The weight and size shall be specified for the instrument and its accessories.
The plugs and sockets shall be specified regarding type and pin interconnections.
The instrument model number and the serial number shall be clearly readable and located in a readily
accessible place.
4.1.6 Environmental effects
The warm-up time necessary for the instrument to reach stable operating conditions within specified
limits shall be stated.
The temperature, humidity and vibration ranges for normal use, storage and transport shall be specified
for the instrument and its accessories.
The instrument shall conform to relevant electromagnetic compatibility (EMC) regulations.
4.2 Electrical characteristics
4.2.1 General
The electrical characteristics of an instrument shall be evaluated after the warm-up time has elapsed.
The electrical characteristics are only valid for the stated operating conditions.
When relevant, the stability of the specified values with time, for specified environmental conditions,
shall be stated.
2 © ISO 2013 – All rights reserved
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SIST EN ISO 15548-1:2014
ISO 15548-1:2013(E)
The electrical characteristics apply to various items of the functional block diagram of the instrument.
Where applicable, they are provided by the manufacturer. Some of these characteristics can be verified
according to the methodology described in Clause 6.
4.2.2 Functional block diagram
The functional block diagram of a typical general-purpose eddy current instrument is shown in Figure 1.
Figure 1 — Functional block diagram of eddy current instrument
4.2.3 Generator unit
The source of excitation is the generator unit.
In the case of alternating excitation (sinusoidal, triangular, rectangular, etc.), the characteristics to be
defined are as follows:
— type of generator: current or voltage;
— type of excitation: single or multifrequency;
— frequency setting: range, step size, deviation from nominal value;
— harmonic distortion;
— amplitude setting: range, step size, deviation from nominal value, maximum output voltage or current;
— source impedance with frequency dependence.
In the case of multifrequency excitation, it shall be stated whether frequencies are injected simultaneously
or multiplexed, independent or related, and the multiplexing sequence shall be specified, when relevant.
4.2.4 Input stage characteristics
The input stage interfaces the probe to the instrument. It provides impedance matching and
amplification, as required.
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SIST EN ISO 15548-1:2014
ISO 15548-1:2013(E)
The characteristics to be defined are as follows:
— input impedance with frequency dependence;
— gain setting range, step size, deviation from nominal value;
— maximum input voltage;
— common-mode operating parameters, when relevant.
4.2.5 Balance
Balance is the compensation of the signal to achieve a predetermined operating point, e.g. zero. The
compensation may be performed manually or automatically, at the input stage, or during HF signal
processing, or during demodulated signal processing, or on the display.
The characteristics to be defined are as follows:
— maximum input range, which can be compensated;
— residual value at balance (expressed as a percentage of a specified range, e.g. full-scale output).
4.2.6 High-frequency signal processing
4.2.6.1 HF filtering
Filters reduce the signal frequency content which can have an undesirable effect on the test result.
The filters used before demodulation are referred to as carrier frequency filters (HF filters). These
are usually band-pass filters which suppress any signal frequencies which do not correspond to the
excitation frequency.
The characteristics to be defined are as follows:
— gain;
— bandwidth at 3 dB attenuation;
— rate of attenuation;
— transient response.
4.2.6.2 HF amplification
The characteristics to be defined are as follows:
— gain setting range, step size, deviation from nominal value;
— input signal range;
— bandwidth;
— output saturation level.
4.2.6.3 Demodulation
Synchronous demodulation extracts the vector components from the HF signal.
For positive polarity of demodulation, a delay in the signal will cause the signal vector to rotate clockwise.
The polarity of demodulation shall be positive and shall be confirmed.
4 © ISO 2013 – All rights reserved
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SIST EN ISO 15548-1:2014
ISO 15548-1:2013(E)
The characteristics to be defined are as follows:
— wave shape of the reference signal, e.g. sine, square, pulse;
— bandwidth for each wave shape of the reference signal;
— phase-dependent amplitude deviations;
— phase-dependent phase deviations.
Amplitude demodulation extracts the low-frequency amplitude variations from the HF signal.
4.2.7 Demodulated signal processing
4.2.7.1 Vector amplification
Vector amplification generally consists of two transmission channels of identical design. These channels
amplify the vector components produced by synchronous demodulation. In some instruments, these
components can be amplified with different gains.
The characteristics to be defined are as follows:
— gain setting range, step size, deviation from nominal value;
— input signal ranges;
— bandwidth;
— output saturation level.
4.2.7.2 LF filtering
The filters used after demodulation are referred to as low-frequency filters (LF filters). The bandwidth
of the filter is chosen to suit the application, e.g. wobble, surface speed, etc.
The characteristics to be defined are as follows:
— gain;
— bandwidth at 3 dB attenuation;
— rate of attenuation;
— transient response.
4.2.7.3 Phase setting
Phase setting permits rotation of the demodulated signal vector on the complex plane display.
The characteristics to be defined are as follows:
— range;
— step size;
— amplitude variation of the signal vector with phase setting;
— deviation of indicated phase rotation from actual phase rotation.
4.2.8 Output and signal display
The type of display can be an indicator display, or a hard-copy display, or a screen display.
© ISO 2013 – All rights reserved 5
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SIST EN ISO 15548-1:2014
ISO 15548-1:2013(E)
The type of presentation can be, for example, complex plane, ellipse, time-synchronous, frequency
spectrum, imaging.
The related characteristics to be defined include:
— size;
— graticule divisions, major and minor;
— full-scale-display voltage range or time range;
— transfer factor e.g. volts/division;
— linearity;
— bandwidth.
The output can be analogue, digitised or logical.
The characteristics of analogue outputs to be defined are as follows:
— voltage or current range;
— output impedance;
— linearity;
— bandwidth.
The characteristics of digitised outputs to be defined are as follows:
— data protocol;
— serial or parallel;
— voltage and current levels;
— speed and format;
— sampling rate;
— analogue/digital A/D resolution, range and linearity.
The characteristics of logical outputs to be defined are as follows:
— voltage and current levels;
— settling delay;
— hysteresis;
— actively high or low.
4.2.9 Digitisation
4.2.9.1 General
Whenever digitisation is performed, the following characteristics shall be defined:
— stage of digitisation in the signal processing;
— digitisation technique;
— A/D resolution;
6 © ISO 2013 – All rights reserved
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SIST EN ISO 15548-1:2014
ISO 15548-1:2013(E)
— sampling rate.
The information supplied by the manufacturer shall therefore include data on the parameters in 4.2.9.2
to 4.2.9.5.
4.2.9.2 Stage of digitisation
Digitisation may be performed either before or after signal demodulation.
4.2.9.3 Digitisation technique
Digitisation can be performed using an internal clock or an external encoder.
4.2.9.4 A/D resolution
Resolution is the nominal value of the converter input voltage corresponding to one digitisation bit.
The number of digitisation bits is equally useful information, even though it can be directly accessed
through the maximum input voltage and the resolution.
4.2.9.5 Sampling rate
The sampling rate is the frequency, in hertz, at which the A/D conversion is made.
5 Verification
5.1 General
For a consistent and effective eddy current examination, it is necessary to verify that the performance of
the component parts of the eddy current test system is maintained within acceptable limits.
The physical condition of the reference blocks shall be verified to be within acceptable limits before
being used to verify the system or probes.
The measuring equipment used for verification shall be in a known state of calibration.
For a better understanding, the verification procedure is described identically in all three parts of ISO 15548.
5.2 Levels of verification
There are three levels of verification. Each level defines the time intervals between verification and the
complexity of the verification.
It is understood that initial type testing has already been carried out by the manufacturer or under his
control.
a) Level 1: Global functional check
A verification is performed at regular intervals of time on the eddy current test system, using
reference blocks to verify that the performance is within specified limits.
The verification is usually performed at the examination location.
The time interval and the reference pieces are defined in the verification procedure.
b) Level 2: Detailed functional check and calibration
A verification on an extended time scale is performed to ensure the stability of selected characteristics
of the eddy current instrument, probe, accessories and reference blocks.
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SIST EN ISO 15548-1:2014
ISO 15548-1:2013(E)
c) Level 3: Characterisation
A verification is performed on the eddy current instrument, probe accessories and reference blocks
to ensure conformity with the characteristics supplied by the manufacturer.
The organization requiring the verification shall specify the characteristics to be verified.
The main features of verification are shown in Table 1.
Table 1 — Verification levels
Level Object Typical time period Instruments Responsible entity
1
Stability of system Frequently,
Global functional Reference blocks User
performance e.g. hourly, daily
check
Stability of selected
2 Less frequently but Calibrated measur-
characteristics of the
Detailed functional at least annually and ing instruments, User
instrument, probes
check and calibration after repair reference blocks
and accessories
All characteristics Calibrated labora-
Once
3 of the instrument, tory measuring
(on release) Manufacturer, user
Characterisation probes and acces- instruments and
and when required
sories reference blocks
5.3 Verification procedure
The characteristics to be verified are dependant on the application. The essential characteristics and the
level of verification shall be specified in a verification procedure.
The examination procedure for the application shall refer to the verification procedure. This can restrict
the number of characteristics to be verified for a defined application.
Sufficient data on the characteristics featured in an instrument, probe and reference piece shall be
provided, in order that verification can be performed within the scope of this part of ISO 15548.
5.4 Corrective actions
Level 1: When the performance is not within the specified limits, a decision shall be made concerning
the product examined since the previous successful verification. Corrective actions shall be made to
bring the performance within the acceptable limits.
Level 2: When the deviation of the characteristic is greater than the acceptable limits specified by the
manufacturer or in the application document, a decision shall be made concerning the instrument, the
probe or the accessory being verified.
Level 3: When the characteristic is out of the acceptable range specified by the manufacturer or by the
application document, a decision shall be made concerning the instrument, the probe or the accessory
being verified.
6 Measurement of electrical characteristics of instrument
6.1 Measuring requirements
All measurements described in the following subclauses are made at the inputs and outputs of the
instrument. These measurements do not require opening the instrument (black-box concept).
Keeping the black-box concept, any alternative method, the equivalence of which shall be
demonstrated, may be used.
8 © ISO 2013 – All rights reserved
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SIST EN ISO 15548-1:2014
ISO 15548-1:2013(E)
Shielded, non-inductive resistors shall be used as loads. The resistors shall have a value of 50 Ω. Additional
measurements may be made with other values of the resistor. However, it needs to be stressed that
the characteristics of an instrument can be significantly altered if a different load is necessary for the
instrument or the application. In such a case, the load used shall be noted in the test report.
The measurements described hereafter shall be made at three values in each decade of the frequency
range, for example, using multiplication factors 1, 2 and 5. For example, in
...
SLOVENSKI STANDARD
kSIST FprEN ISO 15548-1:2013
01-november-2013
1HSRUXãLWYHQRSUHVNXãDQMH2SUHPD]DSUHVNXãDQMH]YUWLQþQLPLWRNRYLGHO
=QDþLOQRVWLDSDUDWRYLQSUHYHUMDQMH ,62)',6
Non-destructive testing - Equipment for eddy current examination - Part 1: Instrument
characteristics and verification (ISO/FDIS 15548-1:2013)
Zerstörungsfreie Prüfung - Technische Ausrüstung für die Wirbelstromprüfung - Teil 1:
Kenngrößen von Prüfgeräten und deren Verifizierung (ISO/FDIS 15548-1:2013)
Essais non destructifs - Appareillage pour examen par courants de Foucault - Partie 1:
Caractéristiques de l'appareil et vérifications (ISO/FDIS 15548-1:2013)
Ta slovenski standard je istoveten z: FprEN ISO 15548-1
ICS:
19.100 Neporušitveno preskušanje Non-destructive testing
kSIST FprEN ISO 15548-1:2013 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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kSIST FprEN ISO 15548-1:2013
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kSIST FprEN ISO 15548-1:2013
FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 15548-1
ISO/TC 135/SC 4
Non-destructive testing — Equipment
Secretariat: AFNOR
for eddy current examination —
Voting begins on:
2013-07-11
Part 1:
Voting terminates on:
Instrument characteristics and
2013-09-11
verification
Essais non destructifs — Appareillage pour examen par courants
de Foucault —
Partie 1: Caractéristiques de l’appareil et vérifications
Please see the administrative notes on page iii
RECIPIENTS OF THIS DRAFT ARE INVITED TO
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DOCUMENTATION.
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Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 15548-1:2013(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
©
NATIONAL REGULATIONS. ISO 2013
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kSIST FprEN ISO 15548-1:2013
ISO/FDIS 15548-1:2013(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2013
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
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kSIST FprEN ISO 15548-1:2013
ISO/FDIS 15548-1:2013(E)
ISO/CEN PARALLEL PROCESSING
This final draft has been developed within the International Organization for Standardization (ISO), and pro-
cessed under the ISO-lead mode of collaboration as defined in the Vienna Agreement. The final draft was
established on the basis of comments received during a parallel enquiry on the draft.
This final draft is hereby submitted to the ISO member bodies and to the CEN member bodies for a parallel
two-month approval vote in ISO and formal vote in CEN.
Positive votes shall not be accompanied by comments.
Negative votes shall be accompanied by the relevant technical reasons.
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kSIST FprEN ISO 15548-1:2013
ISO/FDIS 15548-1:2013(E)
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Eddy current instrument characteristics . 1
4.1 General characteristics . 1
4.2 Electrical characteristics . 2
5 Verification . 7
5.1 General . 7
5.2 Levels of verification . 7
5.3 Verification procedure . 8
5.4 Corrective actions . 8
6 Measurement of electrical characteristics of instrument . 8
6.1 Measuring requirements . 8
6.2 Generator unit . 9
6.3 Input stage characteristics .12
6.4 Signal processing.14
6.5 Output .23
6.6 Digitisation .23
Annex A (informative) Principle of frequency beat method .24
Annex B (informative) Method of measurement of linearity range between output and input .26
Annex C (normative) Alternative measurement of the input impedance .27
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kSIST FprEN ISO 15548-1:2013
ISO/FDIS 15548-1:2013(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2. www.iso.org/directives
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any
patent rights identified during the development of the document will be in the Introduction and/or on
the ISO list of patent declarations received. www.iso.org/patents
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
The committee responsible for this document is ISO/TC 135, Non-destructive Testing, Subcommittee
SC 4, Eddy current methods.
This second edition cancels and replaces the first edition (ISO 15548-1:2008), of which it constitutes a
minor revision. It also incorporates the Correction ISO 15548-1:2008/Cor 1:2010.
ISO 15548 consists of the following parts, under the general title Non-destructive testing — Equipment
for eddy current examination:
— Part 1: Instrument characteristics and verification
— Part 2: Probe characteristics and verification
— Part 3: System characteristics and verification
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kSIST FprEN ISO 15548-1:2013
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kSIST FprEN ISO 15548-1:2013
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 15548-1:2013(E)
Non-destructive testing — Equipment for eddy current
examination —
Part 1:
Instrument characteristics and verification
1 Scope
This part of ISO 15548 identifies the functional characteristics of a general-purpose eddy current
instrument and provides methods for their measurement and verification.
The evaluation of these characteristics permits a well-defined description and comparability of eddy
current equipment.
By careful choice of the characteristics, a consistent and effective eddy current examination system can
be designed for a specific application.
Where accessories are used, these are characterised using the principles of this part of ISO 15548.
This part of ISO 15548 gives neither the extent of verification nor acceptance criteria for the
characteristics. They are given in the application documents.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 12718, Non-destructive testing — Eddy current testing — Vocabulary
ISO 15549, Non-destructive testing — Eddy current testing — General principles
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 12718 apply.
4 Eddy current instrument characteristics
4.1 General characteristics
4.1.1 Type of instrument
a) An instrument has a general-purpose application when the relationship between the measured
quantity and the display or output is established by the user. A range of probes can be connected
to the instrument. The instrument manufacturer shall provide details of the internal electrical
characteristics, in order that the user can design the examination system. The examination system
shall be in accordance with ISO 15549. The user shall be able to vary the value of frequency, gain,
balance (unless an automatic balance is used), phase, filters and gain and zero of the display.
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kSIST FprEN ISO 15548-1:2013
ISO/FDIS 15548-1:2013(E)
b) An instrument is of specific application when the relationship between the measured quantity and
the display or output is explicitly defined in the range of application. The probe is specific to the
instrument. For this type of instrument, this part of ISO 15548 may be partially applied.
4.1.2 Power supply
The instrument can be powered by batteries or by the local AC power supply. The nominal values of voltage,
frequency and power consumption shall be stated, together with the tolerance for correct operation.
4.1.3 Safety
The instrument and its accessories shall meet the applicable safety regulations, for example, electrical
hazard, surface temperature, explosion, etc.
4.1.4 Technology
The instrument can be wholly analogue or partly analogue and partly digital.
The excitation can be single frequency, multifrequency, swept frequency or pulsed.
The instrument can be single or multichannel.
The instrument settings can be manual, remote controlled, stored or preset.
The instrument shall have component outputs and can be with or without a self-contained display.
4.1.5 Physical presentation
The instrument can be portable, cased or rack mounted, with the component parts integrated or modular.
The weight and size shall be specified for the instrument and its accessories.
The plugs and sockets shall be specified regarding type and pin interconnections.
The instrument model number and the serial number shall be clearly readable and located in a readily
accessible place.
4.1.6 Environmental effects
The warm-up time necessary for the instrument to reach stable operating conditions within specified
limits shall be stated.
The temperature, humidity and vibration ranges for normal use, storage and transport shall be specified
for the instrument and its accessories.
The instrument shall conform to relevant electromagnetic compatibility (EMC) regulations.
4.2 Electrical characteristics
4.2.1 General
The electrical characteristics of an instrument shall be evaluated after the warm-up time has elapsed.
The electrical characteristics are only valid for the stated operating conditions.
When relevant, the stability of the specified values with time, for specified environmental conditions,
shall be stated.
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kSIST FprEN ISO 15548-1:2013
ISO/FDIS 15548-1:2013(E)
The electrical characteristics apply to various items of the functional block diagram of the instrument.
Where applicable, they are provided by the manufacturer. Some of these characteristics can be verified
according to the methodology described in Clause 6.
4.2.2 Functional block diagram
The functional block diagram of a typical general-purpose eddy current instrument is shown in Figure 1.
Figure 1 — Functional block diagram of eddy current instrument
4.2.3 Generator unit
The source of excitation is the generator unit.
In the case of alternating excitation (sinusoidal, triangular, rectangular, etc.), the characteristics to be
defined are as follows:
— type of generator: current or voltage;
— type of excitation: single or multifrequency;
— frequency setting: range, step size, deviation from nominal value;
— harmonic distortion;
— amplitude setting: range, step size, deviation from nominal value, maximum output voltage or current;
— source impedance with frequency dependence.
In the case of multifrequency excitation, it shall be stated whether frequencies are injected simultaneously
or multiplexed, independent or related, and the multiplexing sequence shall be specified, when relevant.
4.2.4 Input stage characteristics
The input stage interfaces the probe to the instrument. It provides impedance matching and
amplification, as required.
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kSIST FprEN ISO 15548-1:2013
ISO/FDIS 15548-1:2013(E)
The characteristics to be defined are as follows:
— input impedance with frequency dependence;
— gain setting range, step size, deviation from nominal value;
— maximum input voltage;
— common-mode operating parameters, when relevant.
4.2.5 Balance
Balance is the compensation of the signal to achieve a predetermined operating point, e.g. zero. The
compensation may be performed manually or automatically, at the input stage, or during HF signal
processing, or during demodulated signal processing, or on the display.
The characteristics to be defined are as follows:
— maximum input range, which can be compensated;
— residual value at balance (expressed as a percentage of a specified range, e.g. full-scale output).
4.2.6 High-frequency signal processing
4.2.6.1 HF filtering
Filters reduce the signal frequency content which can have an undesirable effect on the test result.
The filters used before demodulation are referred to as carrier frequency filters (HF filters). These
are usually band-pass filters which suppress any signal frequencies which do not correspond to the
excitation frequency.
The characteristics to be defined are as follows:
— gain;
— bandwidth at 3 dB attenuation;
— rate of attenuation;
— transient response.
4.2.6.2 HF amplification
The characteristics to be defined are as follows:
— gain setting range, step size, deviation from nominal value;
— input signal range;
— bandwidth;
— output saturation level.
4.2.6.3 Demodulation
Synchronous demodulation extracts the vector components from the HF signal.
For positive polarity of demodulation, a delay in the signal will cause the signal vector to rotate clockwise.
The polarity of demodulation shall be positive and shall be confirmed.
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kSIST FprEN ISO 15548-1:2013
ISO/FDIS 15548-1:2013(E)
The characteristics to be defined are as follows:
— wave shape of the reference signal, e.g. sine, square, pulse;
— bandwidth for each wave shape of the reference signal;
— phase-dependent amplitude deviations;
— phase-dependent phase deviations.
Amplitude demodulation extracts the low-frequency amplitude variations from the HF signal.
4.2.7 Demodulated signal processing
4.2.7.1 Vector amplification
Vector amplification generally consists of two transmission channels of identical design. These channels
amplify the vector components produced by synchronous demodulation. In some instruments, these
components can be amplified with different gains.
The characteristics to be defined are as follows:
— gain setting range, step size, deviation from nominal value;
— input signal ranges;
— bandwidth;
— output saturation level.
4.2.7.2 LF filtering
The filters used after demodulation are referred to as low-frequency filters (LF filters). The bandwidth
of the filter is chosen to suit the application, e.g. wobble, surface speed, etc.
The characteristics to be defined are as follows:
— gain;
— bandwidth at 3 dB attenuation;
— rate of attenuation;
— transient response.
4.2.7.3 Phase setting
Phase setting permits rotation of the demodulated signal vector on the complex plane display.
The characteristics to be defined are as follows:
— range;
— step size;
— amplitude variation of the signal vector with phase setting;
— deviation of indicated phase rotation from actual phase rotation.
4.2.8 Output and signal display
The type of display can be an indicator display, or a hard-copy display, or a screen display.
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kSIST FprEN ISO 15548-1:2013
ISO/FDIS 15548-1:2013(E)
The type of presentation can be, for example, complex plane, ellipse, time-synchronous, frequency
spectrum, imaging.
The related characteristics to be defined include:
— size;
— graticule divisions, major and minor;
— full-scale-display voltage range or time range;
— transfer factor e.g. volts/division;
— linearity;
— bandwidth.
The output can be analogue, digitised or logical.
The characteristics of analogue outputs to be defined are as follows:
— voltage or current range;
— output impedance;
— linearity;
— bandwidth.
The characteristics of digitised outputs to be defined are as follows:
— data protocol;
— serial or parallel;
— voltage and current levels;
— speed and format;
— sampling rate;
— analogue/digital A/D resolution, range and linearity.
The characteristics of logical outputs to be defined are as follows:
— voltage and current levels;
— settling delay;
— hysteresis;
— actively high or low.
4.2.9 Digitisation
4.2.9.1 General
Whenever digitisation is performed, the following characteristics shall be defined:
— stage of digitisation in the signal processing;
— digitisation technique;
— A/D resolution;
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kSIST FprEN ISO 15548-1:2013
ISO/FDIS 15548-1:2013(E)
— sampling rate.
The information supplied by the manufacturer shall therefore include data on the parameters in 4.2.9.2
to 4.2.9.5.
4.2.9.2 Stage of digitisation
Digitisation may be performed either before or after signal demodulation.
4.2.9.3 Digitisation technique
Digitisation can be performed using an internal clock or an external encoder.
4.2.9.4 A/D resolution
Resolution is the nominal value of the converter input voltage corresponding to one digitisation bit.
The number of digitisation bits is equally useful information, even though it can be directly accessed
through the maximum input voltage and the resolution.
4.2.9.5 Sampling rate
The sampling rate is the frequency, in hertz, at which the A/D conversion is made.
5 Verification
5.1 General
For a consistent and effective eddy current examination, it is necessary to verify that the performance of
the component parts of the eddy current test system is maintained within acceptable limits.
The physical condition of the reference blocks shall be verified to be within acceptable limits before
being used to verify the system or probes.
The measuring equipment used for verification shall be in a known state of calibration.
For a better understanding, the verification procedure is described identically in all three parts of ISO 15548.
5.2 Levels of verification
There are three levels of verification. Each level defines the time intervals between verification and the
complexity of the verification.
It is understood that initial type testing has already been carried out by the manufacturer or under his
control.
a) Level 1: Global functional check
A verification is performed at regular intervals of time on the eddy current test system, using
reference blocks to verify that the performance is within specified limits.
The verification is usually performed at the examination location.
The time interval and the reference pieces are defined in the verification procedure.
b) Level 2: Detailed functional check and calibration
A verification on an extended time scale is performed to ensure the stability of selected characteristics
of the eddy current instrument, probe, accessories and reference blocks.
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kSIST FprEN ISO 15548-1:2013
ISO/FDIS 15548-1:2013(E)
c) Level 3: Characterisation
A verification is performed on the eddy current instrument, probe accessories and reference blocks
to ensure conformity with the characteristics supplied by the manufacturer.
The organization requiring the verification shall specify the characteristics to be verified.
The main features of verification are shown in Table 1.
Table 1 — Verification levels
Level Object Typical time period Instruments Responsible entity
1
Stability of system Frequently,
Global functional Reference blocks User
performance e.g. hourly, daily
check
Stability of selected
2 Less frequently but Calibrated measur-
characteristics of the
Detailed functional at least annually and ing instruments, User
instrument, probes
check and calibration after repair reference blocks
and accessories
All characteristics Calibrated labora-
Once
3 of the instrument, tory measuring
(on release) Manufacturer, user
Characterisation probes and acces- instruments and
and when required
sories reference blocks
5.3 Verification procedure
The characteristics to be verified are dependant on the application. The essential characteristics and the
level of verification shall be specified in a verification procedure.
The examination procedure for the application shall refer to the verification procedure. This can restrict
the number of characteristics to be verified for a defined application.
Sufficient data on the characteristics featured in an instrument, probe and reference piece shall be
provided, in order that verification can be performed within the scope of this part of ISO 15548.
5.4 Corrective actions
Level 1: When the performance is not within the specified limits, a decision shall be made concerning
the product examined since the previous successful verification. Corrective actions shall be made to
bring the performance within the acceptable limits.
Level 2: When the deviation of the characteristic is greater than the acceptable limits specified by the
manufacturer or in the application document, a decision shall be made concerning the instrument, the
probe or the accessory being verified.
Level 3: When the characteristic is out of the acceptable range specified by the manufacturer or by the
application document, a decision shall be made concerning the instrument, the probe or the accessory
being verified.
6 Measurement of electrical characteristics of instrument
6.1 Measuring requirements
All measurements described in the following subclauses are made at the inputs and outputs of the
instrument. These measurements do not require opening the instrument (black-box concept).
Keeping the black-box concept, any alternative method, the equivalence of which shall be
demonstrated, may be used.
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kSIST FprEN ISO 15548-1:2013
ISO/FDIS 15548-1:2013(E)
Shielded, non-inductive resistors shall be used as loads. The resistors shall have a value of 50 Ω. Additional
measurements may be made with other values of the resistor. However, it needs to be stressed that
the characteristics of an instrument can be significantly altered if a different load is necessary for the
instrument or the application. In such a case, the load used shall be noted in the test report.
The measurements described hereafter shall be made at three values in each decade of the frequency
range, for example, using multiplication factors 1, 2 and 5. For example, in the decade between 10 and
100 kHz use 10, 20 and 50 kHz.
It should be noted that the filter settings used for a specific application will modify the characteristics,
for example, bandwidth, gain setting accuracy and phase-setting accuracy. In this case, the measurement
conditions for verification shall be specified in the application document.
6.2 Generator unit
6.2.1 Excitation frequency
6.2.1.1 Definition and measurement conditions
The frequency shall be measured at the generator output of the instrument loaded in accordance with 6.1.
The percentage deviation from the displayed value is:
VV−
dm
×100 (1)
V
d
where
V is the displayed value;
d
V is the measured value.
m
The maximum modulus of deviation in the total range of frequencies measured shall be reported.
6.2.1.2 Measurement method
The frequency may be measured using the beat frequency method, a frequency meter or a spectrum analyser.
In the case of multifrequency, multiplexed instruments then appropriate instrumentation shall be used,
e.g. spectrum analyser.
6.2.2 Harmonic distortion
6.2.2.1 Definition and measurement conditions
For a generator producing a sinusoidal waveform, the harmonic content is used as a measure of the
deviation from a pure sinusoid.
The harmonic distortion is described by the distortion factor, k.
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ISO/FDIS 15548-1:2013(E)
k is the ratio of the RMS value of harmonics and the RMS value of alternating quantity:
2
kU= U (2)
∑ n
An approximate value is given by:
2 2
UU−
1
k= (3)
U
where
U is the RMS value of the alternating quantity;
U is the RMS value of the first harmonic (fundamental);
1
U is the RMS value of the nth harmonic.
n
The distortion factor shall be measured at the generator output of the instrument loaded in
accordance with 6.1.
In the case of multifrequency instruments, sufficient instrumentation shall be used, e.g. spectrum analyser.
The value to be stated is the maximum distortion factor for each frequency.
6.2.2.2 Measurement method
The distortion factor may be measured using a distortion-factor bridge, a spectrum analyser or a
high-pass filter.
6.2.3 Source impedance
6.2.3.1 Definition and measurement conditions
The source impedance, Z , is the internal impedance of the generator unit (see Figure 2), measured at
s
each independent output.
a) Voltage-driven generator
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