EN 60746-1:2003

SLOVENSKI SIST EN 60746-1:2004

STANDARD
marec 2004
Expression of performance of electrochemical analyzers - Part 1: General
ICS 71.040.40 Referenčna številka
©  Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

EUROPEAN STANDARD EN 60746-1
NORME EUROPÉENNE
EUROPÄISCHE NORM February 2003

ICS 71.040; 19.040
English version
Expression of performance of electrochemical analyzers
Part 1: General
(IEC 60746-1:2003)
Expression des qualités  Angabe zum Betriebsverhalten
de fonctionnement des analyseurs von elektrochemischen Analysatoren
électrochimiques Teil 1: Allgemeines
Partie 1: Généralités (IEC 60746-1:2003)
(CEI 60746-1:2003)
This European Standard was approved by CENELEC on 2003-02-01. 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, Czech Republic,
Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta,
Netherlands, Norway, Portugal, Slovakia, 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

© 2003 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 60746-1:2003 E
Foreword
The text of document 65D/89A/FDIS, future edition 2 of IEC 60746-1, prepared by SC 65D, Analysing
equipment, of IEC TC 65, Industrial-process measurement and control, was submitted to the
IEC-CENELEC parallel vote and was approved by CENELEC as EN 60746-1 on 2003-02-01.

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) 2003-11-01

– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2006-02-01

Annexes designated "normative" are part of the body of the standard.
Annexes designated "informative" are given for information only.
In this standard, annex ZA is normative and annex A is informative.
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 60746-1:2003 was approved by CENELEC as a European
Standard without any modification.
__________
- 3 - EN 60746-1:2003
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
This European Standard incorporates by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text and the
publications are listed hereafter. For dated references, subsequent amendments to or revisions of any
of these publications apply to this European Standard only when incorporated in it by amendment or
revision. For undated references the latest edition of the publication referred to applies (including
amendments).
NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
Publication Year Title EN/HD Year
1) 2)
IEC 60068-1 - Environmental testing EN 60068-1 1994
Part 1: General and guidance
IEC 60359 2001 Electrical and electronic measurement EN 60359 2002
equipment - Expression of performance

1) 2)
IEC 60381-1 - Analogue signals for process control HD 452.1 S1 1984
systems
Part 1: Direct current signals

1) 2)
IEC 60382 - Analogue pneumatic signal for process EN 60382 1993
control systems
1) 2)
IEC 60654-1 - Industrial-process measurement and EN 60654-1 1993
control equipment - Operating
conditions
Part 1: Climatic conditions
1) 2)
IEC 60770-1 - Transmitters for use in industrial- EN 60770-1 1999
process control systems
Part 1: Methods for performance
evaluation
IEC 61298 Series Process measurement and control EN 61298 Series
devices - General methods and
procedures for evaluating performance

1) 2)
ISO 9001 - Quality management systems - EN ISO 9001 2000
Requirements
1) 2)
ISO 9002 - Quality systems - Model for quality EN ISO 9002 1994
assurance in production, installation and
servicing
1)
Undated reference.
2)
Valid edition at date of issue.

Publication Year Title EN/HD Year
1) 2)
ISO 9003 - Quality systems - Model for quality EN ISO 9003 1994
assurance in final inspection and test

INTERNATIONAL IEC
STANDARD 60746-1
Second edition
2003-01
Expression of performance of
electrochemical analyzers –
Part 1:
General
Expression des qualités de fonctionnement
des analyseurs électrochimiques –
Partie 1:
Généralités
© IEC 2003 ⎯ Copyright - all rights reserved
No part of this publication may be reproduced or utilized in any form or by any means, electronic or
mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch  Web: www.iec.ch
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International Electrotechnical Commission
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For price, see current catalogue

– 2 – 60746-1 © IEC:2003(E)
CONTENTS
FOREWORD . 3
INTRODUCTION .4
1 Scope . 5
2 Normative references. 5
3 Terms and definitions . 6
4 Comparison of IEC Standards for Specification and Evaluation.10
5 Procedure for specification .11
5.1 Specification of values and ranges .11
5.2 General .11
5.3 Performance characteristics requiring statements of rated values .12
5.4 Uncertainty limits to be stated for each specified range .12
5.5 Other performance characteristics .13
6 Verification of values .13
6.1 General .13
6.2 Test procedures.15
6.2.1 Intrinsic uncertainty.15
6.2.2 Linearity uncertainty.15
6.2.3 Repeatability.15
6.2.4 Output fluctuation .15
6.2.5 Drift .15
6.2.6 Delay (T ) and 90 % (T ) response times .16
10 90
6.2.7 Warm-up time .16
6.2.8 Variations .16
6.2.9 Primary influence quantities.17
6.2.10 Other influence quantities .17
Annex A (informative) Recommended standard values of influence –
Quantities affecting performance from IEC 60359 .19

60746-1 © IEC:2003(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
EXPRESSION OF PERFORMANCE OF
ELECTROCHEMICAL ANALYZERS –
Part 1: General
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the 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, the IEC publishes International Standards. 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. The 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 the 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 National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60746-1 has been prepared by subcommittee 65D: Analysing
equipment, of IEC technical committee 65: Industrial-process measurement and control.
This second edition cancels and replaces the first edition published in 1982 and constitutes
a technical revision.
The text of this standard is based on the following documents:
FDIS Report on voting
65D/89A/FDIS 65D/93/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.
For this second edition, the text has been changed to reflect revision and introduction of Inter-
national Standards since 1982. An Informative Annex A has been introduced.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this publication will remain unchanged until
2007. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
– 4 – 60746-1 © IEC:2003(E)
INTRODUCTION
This standard specifies the statements which manufacturers should make to describe
analyzers so that users may compare the performance characteristics of any analyzer to their
requirements. It includes the terminology and definitions of the terms to be used in such
statements. It describes the tests that are applicable to all types of electrochemical analyzers,
which may be used to determine these performance characteristics by either the manufacturer
or the user.
This standard is applicable to electrochemical analyzers used for the determination of certain
properties of (generally aqueous) solutions such as pH value, electrical conductivity, dissolved
oxygen content, the concentration of specified ions and redox potential. Other standards in this
series describe those aspects that are particular to specific types of analyzer, for example
IEC 60746-2. It is in accordance with the general principles set out in IEC 60359 and takes into
account documents specifying methods for evaluating performance, IEC 60770 and IEC 61298.
This standard is applicable to analyzers specified for installation in any location and to
analyzers having either flow-through or immersible type sensors. It is applicable to the
complete analyzer when supplied by one manufacturer as an integral unit comprised of all
mechanical, electrical and electronic portions. It also applies to sensor units alone and
electronic units alone when supplied separately or by different manufacturers. For the
purposes of this standard, any regulator for mains-supplied power or any non-mains power
supply, provided with the analyzer or specified by the manufacturer, is considered part of the
analyzer whether it is integral with the analyzer or housed separately.
It does not apply to accessories used in conjunction with the analyzers, such as chart
recorders or data acquisition systems. However, when multiple analyzers are combined and
sold with a single electronic unit for measurements of several properties in parallel,
that read-out unit is considered to be part of the analyzer. Similarly, e.m.f.-to-current or
e.m.f.-to-pressure converters that are not an integral part of the analyzer are not included.
Safety requirements are dealt with in IEC 61010.
Standard ranges of analogue d.c. current and pneumatic signals used in process control
systems are dealt within IEC 60381-1, and IEC 60382.
Specifications for values of influence quantities for the testing of performance characteristics
can be found in IEC 60654-1 and methods of testing in IEC 60068.
Requirements for documentation to be supplied with instruments are dealt with in some
National Standards and also IEC 61187.
General principles concerning quantities, units and symbols are dealt with in ISO 1000.
See also ISO 31, Parts 0 to 13.

60746-1 © IEC:2003(E) – 5 –
EXPRESSION OF PERFORMANCE OF
ELECTROCHEMICAL ANALYZERS –
Part 1: General
1 Scope
This standard is intended:
– to specify the terminology and definitions of terms related to the performance charac-
teristics of electrochemical analyzers used for the continuous determination of certain
aspects of (generally aqueous) solutions;
– to specify uniform methods to be used in making statements on the performance
characteristics of such analyzers;
– to specify general test procedures to determine and verify the performance characteristics
of electrochemical analyzers, taking into account the differences of approach in IEC
documents specifying test methods (IEC 60359, IEC 60770, IEC 61298);
– to provide basic documents to support the application of standards of quality assurance:
ISO 9001, ISO 9002 and ISO 9003.
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 60068-1, Environmental testing – Part 1: General and guidance
IEC 60359:2001, Electrical and electronic measurement equipment – Expression of
performance
IEC 60381-1, Analogue signals for process control systems – Part 1: Direct current signals
IEC 60382, Analogue pneumatic signal for process control systems
IEC 60654-1, Industrial-process measurement and control equipment – Operating conditions –
Part 1: Climatic conditions
IEC 60770-1, Transmitters for use in industrial-process control systems – Part 1: Methods for
performance evaluation
IEC 61298, (all parts): Process measurement and control devices – General methods and
procedures for evaluating performance
ISO 9001, Quality management systems – Requirements
ISO 9002, Quality systems – Model for quality assurance in production, installation and
servicing
ISO 9003, Quality systems – Model for quality assurance in final inspection and test

– 6 – 60746-1 © IEC:2003(E)
3 Terms and definitions
For the purposes of this standard, the following definitions apply. These definitions are based
on those in IEC 60359. Additional definitions from IEC 60770 are included for performance
characteristics appropriate to electrochemical analyzers. The definitions have, in some cases,
been clarified and directed towards relevance to electrochemical analyzers. The reconciliation
of the quantities used to define performance characteristics in this document with those
referred to in IEC 60359, IEC 60770 and IEC 61298 is discussed in clause 4.
3.1
electrochemical analyzer
measuring instrument that provides an indication of a specific property of a medium by use of
a sensor which responds to ions from electrolytes (or ions generated from reactions with
non-electrolytes) in that medium
NOTE The analyzer may comprise of separate parts, see below.
3.2
sensor
that part of the electrochemical analyzer (which may be a separate unit) which is in contact
with the medium in which the property is to be measured
NOTE In general an electrical output related to that property of the sample which is to be measured is derived
from this part of the analyzer. Examples of electrochemical sensors are: pH, ion-sensitive and redox potentiometric
cells, dissolved oxygen cells, conductance cells.
3.3
electronic unit
device converting the electrical signal from the sensor to a defined, scaled, output signal
3.4
simulator
device which provides well-defined electrical properties similar to a specific type of sensor
NOTE It may therefore be used to determine the performance characteristics of the electronic unit alone. It must
exhibit uncertainties that are negligible in comparison with the specifications of performance characteristics to be
determined.
3.5
calibration solution
solution of known value of the property being measured, used for periodic calibration and for
various performance tests.
NOTE 1 The value should be expressed in SI units compatible with ISO 31.
NOTE 2 For the purposes of this Standard, the value of this solution represents the conventional true value
(see 3.8) against which the indicated value is compared.
NOTE 3 The values of calibration solutions should be traceable to reference material according to international or
national standards, or agreed upon by the manufacturer and the user, and the uncertainty of the conventional true
values shall be stated.
3.6
test solution
solution of approximately known value of the property being measured, which is stable in
value over an extended period of time
3.7
true value
value of a quantity which is defined with no uncertainty.
NOTE The true value of a quantity is an ideal concept and, in general, cannot be known exactly.

60746-1 © IEC:2003(E) – 7 –
3.8
conventional true value
value approximating to the true value of a quantity such that, for the purpose for which that
value is used, the difference between the two will be regarded as negligible
NOTE 1 Since the “true value” cannot be known exactly, for the sake of simplicity and where no ambiguity exists,
the term “true value” may be used where the term “conventional true value” is meant.
NOTE 2 See 3.1.13 of IEC 60359.
3.9
performance characteristic
one of the quantities assigned to an apparatus in order to define its performance by values,
tolerances, ranges, etc.
3.10
influence quantity
any quantity, which is not the subject of the measurement but which influences the indication
of the measuring equipment
NOTE Influence quantities may interact in their effect on the measuring equipment.
3.11
variation
difference between the values indicated by an analyzer for the same value of the property
being measured when a single influence quantity assumes successively two different values
3.12
rated value
value assigned to a performance characteristic of the analyzer by the manufacturer
NOTE See 3.3.8 of IEC 60359.
3.13
range
domain between the upper and lower limits of the quantity under consideration
NOTE 1 The term “range” is usually used with a modifier. It may apply to a performance characteristic or an
influence quantity, etc. For example, the Rated Measuring Range is the set of values of the property to be
measured, corresponding to the Output Signal Range of the analyzer (for example 4 mA - 20 mA, etc).
NOTE 2 See 3.3.2 of IE 60359.
3.14
span
difference between the upper and lower limits of the rated measuring range
3.15
performance
quality with which the intended functions of the equipment are accomplished
3.16
reference conditions
appropriate set of influence quantities, with reference values with their tolerances and
reference ranges, with respect to which intrinsic uncertainty is specified
3.17
reference value
specified value of one of a set of reference conditions
NOTE A tolerance may be specified for a reference value.
3.18
reference range
specified range of values of one of a set of reference conditions

– 8 – 60746-1 © IEC:2003(E)
3.19
specified operating range
range of values of a single influence quantity which forms part of the rated operating
conditions
3.20
specified measuring range
set of values of the property to be measured for which the uncertainty of the analyzer is
intended to lie within specified limits
NOTE 1 An instrument can have several specified measuring ranges.
NOTE 2 The specified measuring range can be smaller than the range of values which can be indicated, for
example, on the scale.
NOTE 3 This term used to be known as “effective range”.
3.21
rated operating conditions
set of operating ranges for influence quantities and associated ranges of performance
characteristics within which the variations of an analyzer are specified by the manufacturer
3.22
limit conditions of operation
extreme conditions which an operating instrument can withstand without resulting in damage
or degradation of performance when it is afterwards operated under rated operating conditions
3.23
storage and transport conditions
extreme conditions which an non-operating instrument can withstand without resulting in
damage or degradation of performance when it is afterwards operated under rated operating
conditions
3.24
uncertainty (of measurement)
dispersion of values that may be attributed to the measured quantity
NOTE See 3.1.4 of IEC 60359.
3.25
intrinsic uncertainty
uncertainty when used under reference conditions (see 3.16)
NOTE See 3.1.10, 3.1.11, 3.1.12 of IEC 60359.
3.26
operating uncertainty
uncertainty when used under rated operating conditions (see 3.21)
NOTE See also 3.2.11 of IEC 60359.
3.27
relative uncertainty
ratio of the uncertainty to the conventional true value (when expressed in the same units)
NOTE See 3.3.4 of IEC 60359.
3.28
interference uncertainty
uncertainty caused by substances other than those affecting the measured property being
present in the sample
60746-1 © IEC:2003(E) – 9 –
3.29
linearity uncertainty
maximum deviation between indicated values and a linear function of indicated value versus
the true value of the property being measured, which includes indicated values near the upper
and lower limits of the rated range
NOTE Linearity is a property of the electronic unit and may be verified with a simulator (see 3.4).
3.30
limits of uncertainty
maximum values of uncertainty assigned by the manufacturer to the indicated values of an
analyzer operating under specified conditions
NOTE See 3.3.6 of IEC 60359.
3.31
repeatability
spread of the results of successive measurements at short intervals of time of identical test
material, carried out by the same method, with the same measuring instruments, by the same
observer, in the same laboratory, in unchanged environmental conditions and with no adjust-
ments made by external means to the analyzer under test
NOTE 1 The spread of results should be included in the intrinsic uncertainty (see 3.25).
NOTE 2 A time interval equal to about ten times the 90 % response time of the analyzer may be considered
a short interval between successive measurements.
3.32
hysteresis
difference in indicated values when the same value of the property being measured is applied
but preceded by a lower then a higher value
NOTE If repeatability is specified or measured using approaches from both upscale and downscale direction,
it may include an amount due to hysteresis, i.e., which is not a truly random event. However, the contribution may
be considered to be random when the analyzer is to be applied to applications where the indicated value may
be approached from either direction with equal probability.
3.33
drift
change of indication of an analyzer, for a given value of the property being measured, over a
stated period of time, under reference conditions which remain constant and without any
adjustment to the analyzer by external means
NOTE The rate of change of uncertainty with time should be derived by linear regression.
3.34
output fluctuation
peak-to-peak deviations of the output measured with constant input and constant influence
quantities
3.35
minimum detectable change
change in value of the property to be measured equivalent to twice the output fluctuation
3.36
delay time, T
time interval from the instant a step change in the value of the property being measured
occurs to the instant when the change in the indicated value passes (and remains beyond)
10 % of its steady-state amplitude difference. For cases where the rising delay time and
falling delay time differ, the different delay times should be specified.
3.37
rise (fall) time, T , T
r f
difference between the 90 % response time and delay time

– 10 – 60746-1 © IEC:2003(E)
3.38
90 % response time, T
time interval from the instant a step change occurs in the value of the property being
measured to the instant when the change in the indicated value passes (and remains beyond)
90 % of its steady-state amplitude difference, i.e., T = T + T (or T ). For cases where the
90 10 r f
rising and falling response times differ, the different response times should be specified.
T
T T
10 f
100 %
90 % 10 %
Step
Step
change change
10 % 90 %
100 %
T T
r
T
IEC  3026/02
Figure 1 – Relationship between T T (T ) and T
10, r, f 90
3.39
warm-up time
time interval after switching on the power, under reference conditions, necessary for a unit or
analyzer to comply with and remain within specified limits of uncertainty
NOTE The limits of uncertainty may appropriately be specified equal to the rated intrinsic uncertainty.
4 Comparison of IEC Standards for Specification and Evaluation
The methods for specification of analyzer performance characteristics used by manufacturers
should be compatible with methods for specification of performance requirements by users.
For accurate comparison of manufacturers’ specifications and users' requirements, the para-
meters used to define the performance characteristics of the equipment must be selected
and defined identically.
An electrochemical sensor has particular characteristics primarily determined by chemical
properties, and these can only be slightly modified by constructional techniques. Moreover,
the sensor is directly exposed to a working fluid which can exert a range of influence factors
on the sensor system. This is in contrast to the operation of the purely electrical measuring
devices considered in many other related standards, where the signal is injected electrically
into the instrument's circuits and the sensing of that signal is entirely internal. The approach
to the determination and statement of performance characteristics used in 6.4.2 of IEC 60359
entitled Limits of intrinsic instrumental uncertainty with variations for a single influence
quantity was selected as the best basis for defining the performance of electrochemical type
analyzers. Therefore, requirements for statements in this document are generally given in

60746-1 © IEC:2003(E) – 11 –
accordance with that document, with some performance parameters and test methods based
on IEC 60770.
Alternative approaches adopted in other IEC documents are summarized below, for
comparison:
IEC 61298, Subclause 3.9: Maximum measured uncertainty
A non-statistical test of instrument conformity, where the maximum and minimum
uncertainties are reported from a series of tests. This is particularly appropriate to bat
...