SIST EN 62008:2006

SLOVENSKI STANDARD
SIST EN 62008:2006
01-september-2006
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SRGDWNRYLQSULSDGDMRþHSURJUDPVNHRSUHPH,(&
Performance characteristics and calibration methods for digital data acquisition systems
and relevant software
Leistungseigenschaften und Kalibrierverfahren für digitale Datenerfassungssysteme und
entsprechende Software
Caractéristiques de performance et méthodes d'étalonnage pour les systèmes
d'acquisition de données numériques et logiciels appropriés
Ta slovenski standard je istoveten z: EN 62008:2005
ICS:
35.080
35.160
SIST EN 62008:2006 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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EUROPEAN STANDARD EN 62008
NORME EUROPÉENNE
EUROPÄISCHE NORM October 2005

ICS 33.200


English version


Performance characteristics and calibration methods
for digital data acquisition systems
and relevant software
(IEC 62008:2005)


Caractéristiques de performance  Leistungseigenschaften
et méthodes d'étalonnage und Kalibrierverfahren
pour les systèmes d'acquisition für digitale Datenerfassungssysteme
de données numériques und entsprechende Software
et logiciels appropriés (IEC 62008:2005)
(CEI 62008:2005)






This European Standard was approved by CENELEC on 2005-10-01. CENELEC 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 Central Secretariat or to any CENELEC 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 CENELEC member into its own language and
notified to the Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden,
Switzerland and United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels


© 2005 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 62008:2005 E

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EN 62008:2005 - 2 -
Foreword
The text of document 85/267/FDIS, future edition 1 of IEC 62008, prepared by IEC TC 85, Measuring
equipment for electrical and electromagnetic quantities, was submitted to the IEC-CENELEC parallel
vote and was approved by CENELEC as EN 62008 on 2005-10-01.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2006-07-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2008-10-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 62008:2005 was approved by CENELEC as a European
Standard without any modification.
__________

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- 3 - EN 62008:2005
Annex ZA
(normative)

Normative references to international publications
with their corresponding European publications
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
NOTE Where an international publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
Publication Year Title EN/HD Year
IEC 60748-4 1997 Semiconductor devices - Integrated - -
circuits
Part 4: Interface integrated circuits

1)
IEC 60748-4-3 - Part 4-3: Interface integrated circuits - - -
Dynamic criteria for Analogue-Digital
Converters (ADC)

2) 3)
ISO/IEC 17025 - General requirements for the competence EN ISO/IEC 2005
of testing and calibration laboratories 17025

2)
BIPM/IEC/IFCC/ISO/
- Guide to the expression of uncertainty in - -
IUPAC/IUPAP/OIML
measurement (GUM)





1)
To be published.
2)
Undated reference.
3)
Valid edition at date of issue.

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NORME CEI
INTERNATIONALE
IEC



62008
INTERNATIONAL


Première édition
STANDARD

First edition

2005-07


Caractéristiques de performance et
méthodes d'étalonnage pour les systèmes
d'acquisition de données numériques
et logiciels appropriés

Performance characteristics and calibration
methods for digital data acquisition systems
and relevant software

 IEC 2005 Droits de reproduction réservés  Copyright - all rights reserved
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électronique ou mécanique, y compris la photocopie et les photocopying and microfilm, without permission in writing from
microfilms, sans l'accord écrit de l'éditeur. the publisher.
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Pour prix, voir catalogue en vigueur
For price, see current catalogue

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62008  IEC:2005 – 3 –
CONTENTS
FOREWORD.7
INTRODUCTION.11

1 Scope.13
2 Normative references .13
3 Terms, definitions, abbreviations and symbols.15
3.1 Terms and definitions .15
3.2 Abbreviations and symbols.17
4 General requirements .17
4.1 Test procedures and measurement uncertainty estimation .17
4.2 General requirements for ADMs .19
4.3 Descriptions of parameters.19
4.4 Testing methods of measurable parameters .27
5 Hardware functionality for calibration.51
5.1 Onboard calibration information.51
5.2 General measurement adjustment hardware.51
5.3 Self-adjustment hardware.53
6 Software calibration methods.53
6.1 Calibration application programming interface (API) .53
6.2 Self-calibration methods .53
6.3 External calibration methods .55
7 Calibration procedures .55

Annex A (informative) Examples of calculation of modular DAQ system uncertainty.57
Annex B (normative) Pseudo-code to perform static test by method B (see 4.4.1.2)
and a numerical example .63
Annex C (informative) ADM characteristics .83

Bibliography.93

Figure 1 – Test signals applied to the ADM.31
Figure 2 – Test procedure.35
Figure 3 – Representation in different grey tones of the cumulative histograms
computed in each step in the case of a 5-bit ADM and a test with 4 steps.35
Figure 4 – Test arrangement for noise measurements on ADMs .43
Figure C.1 – Bipolar ADM with true zero .85
Figure C.2 – Bipolar ADM with no true zero .87
Figure C.3 – Offset (specified at step 000).89
Figure C.4 – Gain component of uncertainty (after correction of offset) (specified at
step 011) .91

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62008  IEC:2005 – 5 –
Table 1 – Precision of estimates of code transition level for different record lengths .29
Table 2 – Example of parameters specification of ADM for measurement uncertainty
estimation of DAQ device.49
Table B.1 – Derivation of the amplitude (A) and offset (C ) of the small triangular waves,
j
the number of samples per record (M) and the number of records (R). .73
Table B.2 – Results of the histogram test and corresponding transition voltages for a
5-bit ADM tested by method B in 4 steps .75
Table B.3 – Deriving INL and DNL from the measured transition voltages.79

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62008  IEC:2005 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

PERFORMANCE CHARACTERISTICS AND CALIBRATION METHODS
FOR DIGITAL DATA ACQUISITION SYSTEMS
AND RELEVANT SOFTWARE


FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62008 has been prepared by IEC technical committee 85:
Measuring equipment for electrical and electromagnetic quantities.
The text of this standard is based on the following documents:
FDIS Report on voting
85/267/FDIS 85/268/RVD

Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

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62008  IEC:2005 – 9 –
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

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62008  IEC:2005 – 11 –
INTRODUCTION
Totally automated measurement systems are becoming the norm for manufacturing test,
research and any other area where measurements are made. Measurement automation leads
to extensive data sharing, inter-instrument communication and remote measurement control.
Multifunction data acquisition (DAQ) devices meet these measurement needs. They rely on
standard computer technology, allowing measurement systems developers to leverage open
computer standards. The measurements made by DAQ devices are accurate and traceable.
The need for measurement integrity requires developing standards not only for the
measurement hardware but also for the software that calibrates the hardware.

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62008  IEC:2005 – 13 –
PERFORMANCE CHARACTERISTICS AND CALIBRATION METHODS
FOR DIGITAL DATA ACQUISITION SYSTEMS
AND RELEVANT SOFTWARE


1 Scope
This International Standard specifies performance characteristics and calibration methods for
digital data acquisition systems and relevant software to ensure that all measurement
systems relying on DAQ devices meet a common standard.
This standard covers:
– the minimum specifications that the DAQ device manufacturer must provide to describe
the performance of the analogue-to-digital module (ADM) of the DAQ device;
– standard test strategies to verify the minimum set of specifications;
– the minimum calibration information required by the ADM that is stored on the DAQ device;
– the minimum calibration software requirements for external and self-calibration of the
ADM of the DAQ device.
This standard deals with low frequency signal conversion, e.g. applications such as plant
control, vibration measurement, vibro-diagnostics, acoustics, ultrasonic measurements,
temperature measurements, pressure measurements, measurement in power electronics, etc.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 60748-4:1997, Semiconductor devices – Integrated circuits – Part 4: Interface integrated
circuits
1)
IEC 60748-4-3:___ , Semiconductor devices – Integrated circuits – Part 4-3: Interface
integrated circuits – Dynamic criteria for analogue-to-digital converters (ADC)
ISO/IEC 17025, General requirements for the competence of testing and calibration
laboratories
BIPM, IEC, IFCC, ISO, IUPAC, IUPAP, OIML, Guide to the Expression of Uncertainty in
Measurement (GUM)
———————
1)
To be published.

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62008  IEC:2005 – 15 –
3 Terms, definitions, abbreviations and symbols
3.1 Terms and definitions
For the purposes of this document, the following definitions apply.
3.1.1
analogue-to-digital module
ADM
analogue input of a multifunction DAQ device
3.1.2
application program interface
API
standardized set of subroutines or functions along with the parameters that a program can call.
An API for DAQ devices allows the programmer to communicate and control the operation of
the device
3.1.3
code transition level
value of the input parameter of an ADM at the transition point between two adjacent output
codes. The transition point is defined as the input value that causes 50 % of the output codes
to be less than and 50 % to be greater than or equal to the upper code of the transition. The
transition level T[k] lies between code k -1 and code k
3.1.4
data acquisition device
DAQ
device for entering or collecting data
NOTE Multifunction DAQ devices rely on a personal computer (commercial PC, Industrial PC, Compact PCI,
notebook etc.) for control. These devices are designed to meet the needs of a general-purpose measurement
system. They are not designed for a specific type of measurement. DAQ devices generally provide multiple
measurement modes such as analogue input, analogue output, digital input, digital output, and counter-timer
functionality. This standard only deals with the ADM of a DAQ device.
3.1.5
midstep value
analogue value for the centre of the step excluding the steps at the two ends of the total
range of analogue values
NOTE For the end steps, the midstep value is defined as the analogue value that results when the analogue value
for the transition to the adjacent step is reduced or enlarged as appropriate by half the nominal value of the step
width.
3.1.6
nominal midstep value
specified analogue value within a step that is ideally represented and free of error by the
corresponding digital output code
3.1.7
rated operating conditions
set of conditions that must be fulfilled during the measurement in order that the parameters
determining the measurement uncertainty may be valid.

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62008  IEC:2005 – 17 –
3.1.8
step
the fractional range of analogue input values and the corresponding digital output value.
3.1.9
step width
the absolute value of the difference between the two ends of the range of analogue values
corresponding to one step.
3.2 Abbreviations and symbols
ADM Analogue to digital module
API Application program interface
CMRR Common mode rejection ratio
DAQ Data acquisition device
DIFF Differential
DNL Differential non-linearity
ENOB Effective number of bits
FS Full scale
INL Integral non-linearity
LSB Least significant bit
NRSE Non-referenced single ended
PC Personal computer
RSE Referenced single ended
SINAD Signal to noise and distortion
SFDR Spurious free dynamic range
V Full scale
FS
V Nominal full scale range
FSnom
V Practical full scale range
FSR
V Zero
Z
V Zero scale
ZS
4 General requirements
4.1 Test procedures and measurement uncertainty estimation
A common set of specifications must be presented for comparing the ADM of one DAQ device
to the ADM of another DAQ device. This is especially true when different manufacturers
produce the ADMs. This document includes a core set of information that allows a side-by-
side comparison of ADM capabilities.
DAQ devices are designed to meet their published specifications. If there is a need to verify
these specifications, this standard presents procedures for testing the ADM to confirm the
specifications of the DAQ device.
Using the specifications listed in 4.2, the measurement uncertainty of the ADM of a DAQ
device can be determined.

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62008  IEC:2005 – 19 –
4.2 General requirements for ADMs
The required specifications listed below are a minimum subset of the possible specifications.
The basic parameters describing an ADM include:
– number of channels;
– types of inputs;
– full-scale input range;
– overvoltage protection;
– resolution;
– sampling rate;
– input impedance;
– maximum working voltage;
– rated operating conditions.
2)
The measurable parameters that can be tested include the following :
– gain component of uncertainty;
– offset;
– common mode rejection ratio;
– temperature drift of gain and offset;
– integral non-linearity;
– differential non-linearity;
– noise;
– settling time;
– channel switching error;
– crosstalk;
– analogue input bandwidth.
Where appropriate the following parameters apply:
– signal-to-noise and distortion ratio (SINAD);
– effective number of bits (ENOB);
– spurious free dynamic range (SFDR);
– total harmonic distortion (THD);
– signal to non-harmonic ratio (SNHR).
4.3 Descriptions of parameters
NOTE It is assumed that the input value measured is voltage.
4.3.1 Number of channels
The number of input signals supported by the ADM that can be simultaneously or sequentially
sampled.
———————
2)
Other requirements specific for medium and high frequencies are treated by IEC 60748-4-3.

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62008  IEC:2005 – 21 –
4.3.2 Types of input
Type of input defines how input signals can be connected to the ADM. Possible modes
include:
– referenced single ended (RSE) – an RSE connection is one in which the DAQ device’s
analogue input signal is referenced to a common ground that can be shared with other
input signals;
– non-referenced single ended (NRSE) – an NRSE connection is one in which the DAQ
device’s analogue input signal is referenced to the signal local ground. In this case the
local ground must be different from the analogue ground of the measurement system;
– differential (DIFF) – a DIFF connection is one in which the DAQ device’s analogue input
signal has its own reference signal or signal return path. An ADM with DIFF inputs may
specify input impedance as the impedance between the positive input and negative input
of the ADM. An ADM with DIFF inputs may also specify input impedance as the impedance
between either the positive input and ground or the negative input and ground.
4.3.3 Full-scale input range
The full-scale input range is the total range in analogue values that theoretically can be coded
with constant accuracy by the total number of steps. The full-scale input range is expressed in
volts (see 2.1.18 of IEC 60748-4, Chapter II). Refer to V in Figures C.1 and C.2.
FSnom
4.3.4 Overvoltage protection
Overvoltage protection is the protection of the input circuitry of an ADM from potentially
damaging voltages. Overvoltage protection can be shown for the powered on and powered off
states of the DAQ device. Overvoltage protection is expressed in volts.
4.3.5 Resolution
The degree to which nearly equal values of the analogue input quantity can be distinguished
(see 2.2.1 of IEC 60748-4, Chapter II).
NOTE 1 Numerical resolution is the number (n) of bits necessary to express the total number of steps (see 2.2.2
of IEC 60748-4, Chapter II).
NOTE 2 Analogue resolution (Q) is the nominal value of the step width (see 2.2.3 of IEC 60748-4, Chapter II).
4.3.6 Sampling rate
The number of conversions per unit time. Sampling rate is usually expressed in samples per
second.
4.3.7 Gain component of uncertainty
The difference between the actual and the ideal transition voltages in the transfer diagram at
the specified gain point, after the offset has been adjusted to zero. Gain component of
uncertainty is expressed in % of full-scale input range and should include the warranted time
interval of calibration (see 2.2.5.3 of IEC 60748-4, Chapter II).

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62008  IEC:2005 – 23 –
4.3.8 Offset
The difference between the actual and the ideal first transition levels (see Figure C.3). Offset
is expressed in the units of measure for the ADM and should include the warranted time
interval of calibration (see 2.2.5.2 of IEC 60748-4, Chapter II).
NOTE The first transition level is the transition level where the ADM output changes from 0 to 1. See 3.1.3 for the
definition of code transition level.
4.3.9 Common mode rejection ratio (CMRR)
The ratio of the voltage applied between a specified reference point and the input terminals of
the ADM, when connected together by a specified circuit, to the voltage required between the
input terminals of the ADM to produce the same output.
NOTE The common mode rejection ratio is usually expressed in decibels and may depend upon frequency.
4.3.10 Input impedance
Input impedance is the impedance between the signal input of the ADM and signal common.
Input impedance must be specified when the ADM is powered on, powered off, and when
isolated input limits are overloaded (if applicable).
4.3.11 Temperature drift of gain and offset
Temperature drift of gain is expressed in % of full scale input range per degree Celsius.
Temperature drift of offset is expressed in units of measure for the ADM per degree Celsius.
4.3.12 Integral non-linearity (INL)
The difference between the actual analogue value at the transition between any two adjacent
steps and its ideal value, after offset and gain component of uncertainty have been adjusted
to zero. Integral non-linearity describes the difference between the actual value and the ideal
value of the analogue quantity. INL is expressed in LSB.
4.3.13 Differential non-linearity (DNL)
The difference between the actual step width and the ideal value. DNL is expressed in LSB.
4.3.14 Maximum working voltage
Maximum working voltage is the highest voltage that should be applied to an ADM in normal
use. The working voltage is normally well under the breakdown voltage for safety margin. The
maximum working voltage is the sum of the actual signal voltage and the common mode
voltage and is expressed in volts.
4.3.15 Noise
Noise is any deviation between the ADM output signal (converted to input units) and the ADM
input signal except for deviations caused by linear time invariant system response (gain and
phase shift), a DC level shift, or a deviation in the sample rate. For example, noise includes
the effects of random deviations, fixed pattern deviations, nonlinearities, time base deviations
(fixed deviation in sample time and aperture uncertainty, also known as jitter) and the

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62008  IEC:2005 – 25 –
undesirable infiltration of internal digital signals to the analogue part. Noise is expressed in
the units of measure for the ADM.
NOTE 1 For DC or very low frequency input signals it is usual to describe system noise as measured in 4.4.7,
which does not include the effect of non-linearity and time base deviations.
NOTE 2 SINAD and ENOB include the effects of non-linearity and time base deviations.
4.3.16 Settling time for single channel measurements
The time it takes the ADM to reach a certain accuracy and stay within that accuracy. Settling
time is expressed in seconds required to achieve the given accuracy range. Settling time for
single channel measurements is defined for an ADM measuring a step signal on a si
...