SIST EN 61069-6:1998
(Main)Industrial-process measurement and control - Evaluation of system properties for the purpose of system assessment -- Part 6: Assessment of system operability
Industrial-process measurement and control - Evaluation of system properties for the purpose of system assessment -- Part 6: Assessment of system operability
EN following parallel vote
Leittechnik für industrielle Prozesse - Ermittlung der Systemeigenschaften zum Zweck der Eignungsbeurteilung eines Systems -- Teil 6: Eignungsbeurteilung der Systembedienbarkeit
Mesure et commande dans les processus industriels - Appréciation des propriétés d'un système en vue de son évaluation -- Partie 6: Evaluation de l'opérabilité d'un système
Industrial-process measurement and control - Evaluation of system properties for the purpose of system assessment - Part 6: Assessment of system operability (IEC 61069-6:1998)
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Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 61069-6:1998
01-november-1998
Industrial-process measurement and control - Evaluation of system properties for
the purpose of system assessment - Part 6: Assessment of system operability (IEC
61069-6:1998)
Industrial-process measurement and control - Evaluation of system properties for the
purpose of system assessment -- Part 6: Assessment of system operability
Leittechnik für industrielle Prozesse - Ermittlung der Systemeigenschaften zum Zweck
der Eignungsbeurteilung eines Systems -- Teil 6: Eignungsbeurteilung der
Systembedienbarkeit
Mesure et commande dans les processus industriels - Appréciation des propriétés d'un
système en vue de son évaluation -- Partie 6: Evaluation de l'opérabilité d'un système
Ta slovenski standard je istoveten z: EN 61069-6:1998
ICS:
25.040.40 Merjenje in krmiljenje Industrial process
industrijskih postopkov measurement and control
SIST EN 61069-6:1998 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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NORME
CEI
INTERNATIONALE
IEC
61069-6
INTERNATIONAL
Première édition
STANDARD
First edition
1998-04
Mesure et commande dans
les processus industriels –
Appréciation des propriétés d’un système
en vue de son évaluation –
Partie 6:
Evaluation de l’opérabilité d’un système
Industrial-process measurement and control –
Evaluation of system properties for the purpose
of system assessment –
Part 6:
Assessment of system operability
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For price, see current catalogue
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61069-6 IEC:1998 – 3 –
CONTENTS
Page
FOREWORD . 5
INTRODUCTION . 9
Clause
1 Scope. 13
2 Normative references. 13
3 Definitions. 15
4 Operability properties. 15
4.1 General. 15
4.2 Operability efficiency. 19
4.3 Operability intuitiveness. 19
4.4 Operability transparency. 21
4.5 Operability robustness. 21
5 Review of the system requirements document (SRD). 23
6 Review of the system specification document (SSD) . 23
7 Assessment procedure. 25
7.1 General. 25
7.2 Analysis of the system requirements document and system specification document . 25
7.3 Designing the assessment programme . 27
7.4 Assessment programme. 29
8 Evaluation techniques. 31
8.1 General. 31
8.2 Analytical evaluation techniques . 35
8.3 Empirical evaluation techniques . 37
8.4 Influencing conditions. 39
9 Execution and reporting of the assessment. 39
Annexes
A (informative) Phases of a system life cycle . 41
B (informative) Guide on factors to look for when reviewing the operability requirements
stated in the system requirements document . 43
C (informative) Bibliography. 49
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61069-6 IEC:1998 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
INDUSTRIAL-PROCESS MEASUREMENT AND CONTROL –
EVALUATION OF SYSTEM PROPERTIES FOR THE PURPOSE
OF SYSTEM ASSESSMENT –
Part 6: Assessment of system operability
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 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 61069-6 has been prepared by subcommittee 65A: System aspects,
of IEC technical committee 65: Industrial-process measurement and control.
The text of this standard is based on the following documents:
FDIS Report on voting
65A/246/FDIS 65A/251/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.
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61069-6 IEC:1998 – 7 –
The relation of this part to the other parts of IEC 61069 and the relative place of this part within
this standard is shown in figure 1.
Part 1 provides the overall guidance and as such is intended as a "stand-alone" publication.
Part 2 details the assessment methodology.
Parts 3 to 8 provide guidance on the assessment of specific groups of properties.
The division of properties in parts 3 to 8 have been chosen so as to group together related
properties.
IEC 61069 consists of the following parts, under the general title: Industrial-process
measurement and control. Evaluation of system properties for the purpose of system
assessment:
Part 1: General considerations and methodology
Part 2: Assessment methodology
Part 3: Assessment of system functionality
Part 4: Assessment of system performance
Part 5: Assessment of system dependability
Part 6: Assessment of system operability
1)
Part 7: Assessment of system safety
1)
Part 8: Assessment of not task related system properties
Annexes A, B and C are for information only.
___________
1)
To be published.
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61069-6 IEC:1998 – 9 –
INTRODUCTION
This part of IEC 61069 deals with the method which should be used to assess the operability of
industrial process measurement and control systems.
Assessment of a system is the judgement, based on evidence, of the system's suitability for a
specific mission or class of missions.
To obtain total evidence would require complete (i.e. under all influencing conditions)
evaluation of all system properties relevant to the specific mission or class of missions.
Since this is rarely practical, the rationale on which an assessment of a system should be
based is:
– to identify the criticality of each of the relevant system properties;
– to plan for evaluation of the relevant system properties with a cost-effective dedication of
effort to the various properties.
In conducting an assessment of a system it is crucial to bear in mind the need to gain a
maximum increase in confidence in the suitability of a system within practical cost and time
constraints.
An assessment can only be carried out if a mission has been stated (or given) or if any mission
can be hypothesized. In the absence of a mission, no assessment can be made, however
evaluations (as defined in IEC 61069-1) can still be specified and be carried out for use in
assessments performed by others.
In such cases, the standard can be used as a guide for planning an evaluation and it provides
procedures for performing evaluations, since evaluations are an integral part of assessment.
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61069-6 IEC:1998 – 11 –
Part 1
General considerations
and methodology
Scope
Definitions
Basis of assessment
Assessment consideration
The system
Properties
Influencing conditions
Assessment procedure
Definition of the objectives
Design and layout
Part 2
Methodology
Analysis of objectives
Analysis of system requirements
Analysis of system specification
Planning Design of assessment programme
Facilities
Expertise
Time
Funds
Protocol Execution of assessment programme
Monitor and control
Part 3: Functionality
Part 4: Performance
Part 5: Dependability
Part 6: Operability
Part 7: Safety
Part 8: NTR properties
Assessment report
Figure 1 – General layout of IEC 61069
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61069-6 IEC:1998 – 13 –
INDUSTRIAL-PROCESS MEASUREMENT AND CONTROL –
EVALUATION OF SYSTEM PROPERTIES FOR THE PURPOSE
OF SYSTEM ASSESSMENT –
Part 6: Assessment of system operability
1 Scope
This part of IEC 61069 covers the assessment of the operability of industrial process
measurement and control systems.
The assessment methodology detailed in IEC 61069-2 is applied to obtain the operability
assessment programme.
The subsidiary operability properties are analysed, and criteria to be taken into account when
assessing operability is described.
References are made to different supplementary operability evaluation techniques.
2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this part of IEC 61069. At the time of publication, the editions indicated
were valid. All normative documents are subject to revision, and parties to agreements based
on this part of IEC 61069 are encouraged to investigate the possibility of applying the most
recent editions of the normative documents indicated below. Members of IEC and ISO maintain
registers of currently valid International Standards
IEC 61069-1:1991, Industrial-process measurement and control – Evaluation of system
properties for the purpose of system assessment – Part 1: General considerations and
methodology
IEC 61069-2:1993, Industrial-process measurement and control – Evaluation of system
properties for the purpose of system assessment – Part 2: Assessment methodology
IEC 61069-3:1996, Industrial-process measurement and control – Evaluation of system
properties for the purpose of system assessment – Part 3: Assessment of system functionality
IEC 61069-4:1997, Industrial-process measurement and control – Evaluation of system
properties for the purpose of system assessment – Part 4: Assessment of system performance
IEC 61069-8,— Industrial-process measurement and control – Evaluation of system properties
1)
for the purpose of system assessment – Part 8: Assessment of not task related properties
ISO 9241-10:1996, Ergonomic requirements for office work with visual display terminals (VDTs) –
Part 10: Dialogue principles
___________
1)
To be published.
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61069-6 IEC:1998 – 15 –
3 Definitions
For the purpose of this part of IEC 61069 the following definitions apply:
3.1
operability
the extent to which the operating means provided by the system are efficient, intuitive,
transparent and robust to accomplish the operators’ tasks
3.2
operator
the person (or persons) who use(s) the system to fulfill the mission
NOTE – In this standard operator is used in a generic way and includes all persons who may perform any tasks to
fulfill the mission.
3.3
efficiency
the extent to which the operating means provided by the system minimise operator time and
effort required in using the system to accomplish his tasks within stated constraints
3.4
intuitiveness
the extent to which the operating means provided by the system are immediately under-
standable by the operators
3.5
transparency
the extent to which the operating means provided by the system apparently places the operator
in direct contact with his tasks
3.6
robustness
the extent to which the system correctly interprets and responds to operator actions performed,
using unambiguous methods and procedures, and removes ambiguities by providing appro-
priate feedback
4 Operability properties
4.1 General
For a system to be operable it is necessary that it provides the operator through its human-
machine interface with a transparent and consistent window into the tasks to be performed. It
should have means for efficient, intuitive, transparant and robust interaction with these tasks.
The extent to which this is the case can be expressed by the property operability.
The human-machine interface functions are part of the system and enable the operator to
monitor and manipulate the system itself, the external systems and the process.
The requirements for operability are strongly affected by the skill, knowhow and constitution of
the personnel operating the system.
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61069-6 IEC:1998 – 17 –
During its life cycle the system is required to provide various degrees of operability depending
on the phases of the system mission as discussed in IEC 61069-2, 5.2.
Operability requirements can differ between these phases of the life cycle of the system. They
depend upon the tasks to be performed during the phase and the duration of the phase.
The operability requirements can be high, where the duration of a phase is short and its
relevance for the system mission high; the requirements can be low, where the duration of a
phase is long, so that sequences of required actions for certain operations can be learnt by the
operator over the long term the system is used.
Hence, the relative importance of each of the tasks for the mission and the duration of the
phases, during which these tasks are to be performed should clearly be stated in the system
requirements document.
In the assessment of operability one is concerned with the way information, given by the
operator to the system (such as commands and requests), is processed by the system, as well
as the transparency of information coming from the system to the operator, such as
process/system state and values, trends, reports, etc.
While special operability measures are sometimes required during the design and/or
maintenance phases of the system, the operability requirements are mostly understood as
those necessary during the operational phase of an industrial process plant.
However all phases are of importance. During each phase the system will typically be operated
by a different group of operators, with different operability requirements.
In addition, planned, unplanned and disturbed plant operation can require different operating
schemes and hence operability requirements.
Annex A shows the various phases, the operator(s) using the system during these phases,
their typical tasks and the type of interfaces utilized.
The perception of the property operability of the system by the operators is strongly affected by
the property performance (especially speed of response), refer to IEC 61069-4, and to the
property functionality of the system, refer to IEC 61069-3, see also 7.2.2.
Within operability four subproperties can be identified, their interrelation is shown in
figure 2.
Operability
Efficiency Intuitiveness Transparency Robustness
Figure 2 – Subproperties of operability
Operability cannot be expressed as a single number.
Some aspects can be quantified by analysing the ergonomic aspects of the subproperties, and
by measuring the number of actions and time required to accomplish a given task (the
efficiency of the human-machine interface), others can be qualified in a descriptive way.
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61069-6 IEC:1998 – 19 –
4.2 Operability efficiency
A system has operability efficiency, if it allows the operator, with a minimum risk of making
errors, to perform his task(s) with a minimum amount of mental and physical effort within an
acceptable time frame.
The extent to which is a measure of the operability efficiency of the system.
The operability efficiency depends, among others, on the following elements:
– the ergonomic design of the devices (keyboard, mouse, voice input, dedicated knobs,
screens, indicators, etc.) used as operating means in support of the human-machine
interface;
– the geographical lay-out, the number of these devices and their relative location on the
operators’ workplace;
– the shape of the operators’ workplace;
– the method and procedures to be used to retrieve information, to issue commands, etc.
Efficiency cannot be quantified as a single number. However it can be expressed by a
qualitative description containing some quantified elements, such as:
– a coverage factor, obtained by comparing the operating means provided by the system with
the specific requirements as stated in the system requirements document and the applicable
ergonomic standards; and
– the time required to give a command, and to request information.
4.3 Operability intuitiveness
The operating means provided by the system, which enable the operators to give commands
and which present information to the operators should not be in conflict with the skills,
educational level and general culture of the operators, who are performing tasks, by using the
functions provided by the system.
The degree to which the operational means are consistant with common working practices is a
measure of the operability intuitiveness of the system.
Intuitiveness depends on the following factors:
– the extent to which standard generic procedures, rules and methods for the operation of
“action” elements are followed;
– the conventions followed to present information to the operator, for example red for
emergency conditions, etc.;
– the conventions followed to give commands, for example turning a knob clockwise to
increase a value, etc.
Unlike other properties intuitiveness is not a totally inherent property of the system. It can only
be expressed with respect to a particular user domain.
This domain can be defined in terms of culture, international and/or proprietary standards, etc.
Intuitiveness cannot be quantified by a single number. However it can be expressed by a
qualitative description containing some quantified elements, such as a coverage factor
obtained by comparing the operating means provided by the system with the specific
requirements as stated in the system requirements document.
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61069-6 IEC:1998 – 21 –
4.4 Operability transparency
The operating means provided by the system, which enable the operator to give commands
and which present information to the operator, should give the operator a realistic view of the
actions (and their sequence) to be taken to complete the task(s) to be performed.
The extent to which these means are provided is a measure of the operability transparency of
the system.
The transparency depends on the following factors:
– the logical principles followed to present the functional- and geographical structure of the
process and the tasks to be performed by the operator;
– the way in which labels and names are used to identify the operating means, and the
consistency of their use;
– the consistency in the application of colours, names, audible signals, etc. throughout all
tasks and levels of information;
– the way the dynamics of the tasks are realistically simulated, to give the operator a “real”
feel of the task to be performed, etc.
The information presented by the system should be clear, concise, unambiguous and non
contradictory. If the information is not self-descriptive, it should be explained by a more
detailed description in easily accessible documentation or a help function.
Transparancy cannot be quantified by a single number. However it can be expressed by a
qualitative description containing some quantified elements, such as a coverage factor
obtained by comparing the operating means provided by the system with the specific
requirements as stated in the system requirements document.
4.5 Operability robustness
The operating means provided by the system to enable the operator to give commands should
correctly interpret and respond to any operator action if these are unambiguous and if not,
additional information should be requested by the system to remove the ambiguities. The
degree to which this is done is a measure of the operational robustness of the system.
Robustness depends on the following factors:
– the extent to which deviation from the standard generic rules is permitted, and is
interpreted;
– the extent to which the system is able to detect and notify deviations and to couple these
deviations with requests for further information, etc.
Robustness cannot be quantified by a single number. However it can be expressed by a
qualitative description containing some quantified elements, such as a coverage factor
obtained by comparing the operating means provided by the system with the specific
requirements as stated in the system requirements document to retrieve data, give commands,
etc.
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61069-6 IEC:1998 – 23 –
5 Review of the system requirements document (SRD)
The system requirements document should be reviewed to check that all the tasks to be
performed by the operator using the system and the operability requirements for the task have
been addressed and are listed as described in IEC 61069-2, and in particular its clause 5.
The effectiveness of the operability assessment is strongly dependent upon the compre-
hensiveness of the statements of requirements.
Particular attention should be given to check that for each of the system tasks the operability
requirements are given with respect to:
– the phase of the system life cycle during which the task should be performed;
– the duration of each phase and task(s);
– the minimum and maximum number of operators, who should use the human interface at
the same time to perform the task(s);
– information about the profiles of the operators involved, such as their education,
responsibility, role, skill and preknowledge, etc.;
– protocols and methods to be used, especially aspects requiring the operators to use the
system at the same time.
Annex B gives guidance on factors which can control the operability requirements and should
have been addressed in the system requirements document.
The operability requirements should have been addressed both in relation to individual tasks as
well as in relation to the total mission.
6 Review of the system specification document (SSD)
The system specification document should be reviewed to check that the operability properties
for each of the required tasks are listed as described in IEC 61069-2, and in particular its
clause 6.
Particular attention should be paid to check that information, on a task-by-task basis, is
given on:
– the functions proposed to support the operability aspects of each task;
– for each function the modules and elements, both hardware and software, supporting the
function;
NOTE – The level of detailing the implementation of the task(s) and the extent of subdivision into modules and
elements should be only that which is necessary, yet sufficient to demonstrate that the requirements are met.
– the way in which the interaction is provided for the operator by the proposed system in terms
of devices, methods and procedures;
NOTE – Depending on the architecture of the system, task(s) may be supported by alternative sets of functions,
which can require alternative sequences of operations at the human-machine interface.
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61069-6 IEC:1998 – 25 –
– the skills, experience, etc. to be required by the operators to operate the system properly,
and the tools provided in support of the operation through the human-machine interface;
– the underlying rationale if the system proposed differs from the requirements or if different
alternative solutions are suggested, supported by data, for example standards, field
experience, test reports, calculations, etc.
The review should in particular examine whether for each operational phase the necessary
information is given how the required tasks can be performed with the given group of
personnel.
7 Assessment procedure
7.1 General
The assessment should follow the procedure as laid down in clause 7 of IEC 61069-2.
The objective of the assessment shall be clearly stated. Guidance is given in IEC 61069-1, 4.1.
The information given in the system requirements document (SRD) and the system
specification document (SSD) should be complete and precise to enable the assessment of the
operability.
If during any phase the assessment information is missing or incomplete, the originators of the
SRD and the SSD should be consulted with specific questions to obtain the required additional
information.
7.2 Analysis of the system requirements document and system specification document
7.2.1 Collation of documented information
For the purpose of the assessment of operability, the information related to operability shall be
extracted from the system requirements document (SRD) and the system specification
document (SSD) as described in IEC 61069-2, 7.2.
The requirements as stated in the SRD and the data on the operability aspects of the system
as given in the SSD should be drawn together and cross-related, to compile precise and
concise statements, in qualitative and quantitative terms and, if applicable, their range of
values of the following:
– the operability properties required for each of the tasks and for the system, arranged in
order of the relevant phase or phases of the system life cycle;
– the knowhow, experience and skill of the operators using the interface to perform each of
the tasks defined in the SRD;
– the number of generators and their grouping for tasks which require operators to use the
human-machine interface simultaneously.
Depending on the phase of the system life cycle, assessment of operability can only be done
with existing or similar systems in operation. These assessments should include the prior
knowledge, skill and experience of the system designer, the plant-shift supervisors, the system
maintenance personnel, etc.
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61069-6 IEC:1998 – 27 –
7.2.2 Conditions influencing operability
In IEC 61069-1, 4.4 and IEC 61069-2, 5.5 external and internal conditions are discussed, which
can influence the correct working of the system properties.
The property operability can in particular be sensitive to the following external factors:
– tasks: unusual or infrequent operating scenar
...
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