Industrial-process measurement and control - Evaluation of system properties for the purpose of system assessment - Part 3: Assessment of system functionality
Describes in detail the method to be used to systematically assess the functionality of an industrial-process measurement and control system.
Leittechnik für industrielle Prozesse - Ermittlung der Systemeigenschaften zum Zweck der Eignungsbeurteilung eines Systems - Teil 3: Eignungsbeurteilung der Systemfunktionalität
Mesure et commande dans les processus industriels - Appréciation des propriétés d'un système en vue de son évaluation - Partie 3: Evaluation de la fonctionnalité d'un système
Décrit en détails la méthode à utiliser pour évaluer de manière systématique la fonctionnalité d'un système de mesure et commande des processus industriels.
Industrial-process measurement and control - Evaluation of system properties for the purpose of system assessment - Part 3: Assessment of system functionality (IEC 61069-3:1996)
Standards Content (sample)
SIST EN 61069-3:1998
Industrial-process measurement and control - Evaluation of system properties for
the purpose of system assessment - Part 3: Assessment of system functionality
Industrial-process measurement and control - Evaluation of system properties for thepurpose of system assessment -- Part 3: Assessment of system functionality
Leittechnik für industrielle Prozesse - Ermittlung der Systemeigenschaften zum Zweckder Eignungsbeurteilung eines Systems -- Teil 3: Eignungsbeurteilung der
Mesure et commande dans les processus industriels - Appréciation des propriétés d'un
système en vue de son évaluation -- Partie 3: Evaluation de la fonctionnalité d'unsystème
Ta slovenski standard je istoveten z: EN 61069-3:1996
25.040.40 Merjenje in krmiljenje Industrial process
industrijskih postopkov measurement and control
35.240.50 Uporabniške rešitve IT v IT applications in industry
SIST EN 61069-3:1998 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.---------------------- Page: 1 ----------------------
Mesure et commande dans les processus
Appréciation des propriétés d'un système
en vue de son évaluation –
Evaluation de la
fonctionnalité d'un système
Industrial-process measurement and control –
Evaluation of system properties for
the purpose of system assessment –
Assessment of system functionality
© IEC 1996 Droits de reproduction réservés — Copyright - all rights reserved
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• • For price, see current catalogue
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1069-3 © IEC:1996 – 3 –
1 Scope 13.
2 Normative references 13
3 Definitions 13
4 Functionality properties 15
4.1 General 15
4.2 Functionality 15
4.3 Coverage 15
4.4 Configurability 17
4.5 Flexibility 19
5 Review of system requirements document (SRD) 21
6 Review of system specification document (SSD) 21
7 Assessment procedure 23
7.1 General 23
7.2 Analysis of the system requirements document and
system specification document 23
7.3 Designing the assessment programme 25
7.4 Assessment programme 27
8 Evaluation techniques 27
8.1 General 27
8.2 Coverage 27
8.3 Configurability 27
8.4 Flexibility 29
9 Execution and reporting of the assessment 29
1 General layout of IEC 1069 11
2 Functionality hierarchy 15
3 Configuration methods 17
A Checklist on information to be given in the system requirements document 31
B Example analysis of system requirements document and system specification
document and documentation of collated information 33
C Bibliography 51
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1069-3 © IEC:1996 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
INDUSTRIAL-PROCESS MEASUREMENT AND CONTROL –
EVALUATION OF SYSTEM PROPERTIES FOR
THE PURPOSE OF SYSTEM ASSESSMENT –
Part 3: Assessment of system functionality
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 agreementbetween the two organizations.
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 hasrepresentation from all interested National Committees.
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 thatsense.
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 clearlyindicated in the latter.
The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for anyequipment 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. IEC shall not be held responsible for identifying any or all such patent rights.International Standard IEC 1069-3 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:
Report on voting
Full information on the voting for the approval of this standard can be found in the report onvoting indicated in the above table.
The relation of this part to the other parts of IEC 1069 and the relative place of this partwithin 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.---------------------- Page: 4 ----------------------
1069-3 © IEC:1996 -
The division of properties in parts 3 to 8 have been chosen so as to group together relatedproperties.
IEC 1069 consists of the following parts, under the general title:
measurement and control - Evaluation of system properties for the purpose of systemassessment:
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 (under consideration)
Part 7: Assessment of system safety (under consideration)
Part 8: Assessment of non-task-related system properties
Annexes A, B and C are for information only.
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1069-3 © IEC:1996 - 9 -
This part of IEC 1069 deals with the method which should be used to assess the
functionality of industrial-process measurement and control systems. Assessment of a
system is the judgement, based on evidence, of a system's suitability for a specific missionor class of missions.
To obtain total evidence would require a 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 bebased 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 dedicationof 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 timeconstraints.
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 1069-1) can still be specified and be carried out foruse 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 ofassessment.
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1069-3 © IEC:1996 - 11 -
Basis of assessment
Definition of the objectives
Design and layout
Analysis of objectives
Analysis of system requirements
Analysis of system specification
Planning Design of assessment programme
Execution of assessment programme
Monitor and control
Part 3: Functionality
Part 4: Performance
Part 5: Dependability
Part 6: Operability
Part 7: Security
Part 8: NTR properties
Figure 1 - General layout of IEC 1069
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1069-3 © IEC:1996 – 13 –
INDUSTRIAL-PROCESS MEASUREMENT AND CONTROL –
EVALUATION OF SYSTEM PROPERTIES FOR
THE PURPOSE OF SYSTEM ASSESSMENT –
Part 3: Assessment of system functionality
This part of IEC 1069 describes in detail the method to be used to systematically assess thefunctionality of an industrial-process measurement and control system.
The assessment methodology detailed in IEC 1069-2 is applied to obtain the functionalityassessment programme.
The subsidiary functionality properties are analysed, and criteria to be taken into accountwhen assessing functionality are described.
2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this part of IEC 1069. At the time of publication, the editions
indicated were valid. All normative documents are subject to revision, and parties making
agreements based on this part of IEC 1069 are encouraged to investigate the possibility of
applying the most recent editions of the normative documents indicated below. Members ofIEC and ISO maintain registers of currently valid International Standards.
IEC 1069-1: 1991, Industrial-process measurement and control – Evaluation of system
properties for the purpose of system assessment – Part 1: General considerations andmethodology
IEC 1069-2: 1993, Industrial process measurement and control – Evaluation of systemproperties for the purpose of system assessment – Part 2: Assessment methodology
For the purpose of this part of IEC 1069 the following definitions apply:
The extent to which the system provides, and facilitates assembly of,
functions to perform industrial process measurement and control tasks.
3.2 coverage: The extent to which the system provides functions to perform industrial-process measurement and control tasks.
3.3 configurability: The extent to which the system facilitates selection, setting up and
arrangement of its modules to perform industrial-process measurement and control tasks.3.4 flexibility: The extent to which the system can be adapted.
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IEC:1996 – 15 –
4 Functionality properties
A system is able to perform the required industrial-process measurement and control tasks
if the functions provided by the system cover these tasks. The extent to which this is thecase can be expressed as the property coverage.
For a system designed for a set of rigid and fixed tasks, coverage can describe fully the .
functionality of a system.
The tasks required, however, can differ for different applications of the system or the taskscan change or be extended over time due to changes in the industrial process or
arrangements in control strategy. To cope with this, the system should provide means for
configuring the selection and arrangement of modules, and should have an architecturewhich provides flexibility for additions and. modifications.
To fully assess the functionality of a system it is therefore necessary to identify and assessthe subsidiary properties that determine functionality.
The relation between functionality and its subsidiary properties is shown in figure 2.Functionality
Coverage Configurability Flexibility
Figure 2 – Functionality hierarchy
Functionality cannot be assessed directly and cannot be described by a single measure. It isnecessary to assess each subsidiary property individually.
Some of its sub-properties can be expressed in quantitative terms as an absolute or relative
value, others can only be described in a qualitative way with some quantitative elements.The sub-properties are deterministic in nature.
When assessing the functionality of a system the availability of facilities necessary tosupport the subsidiary properties should be taken into account.
Coverage is determined by:
– the range of distinct functions provided, each differentiated by type, executionfrequency, data volume, etc.;
the way in which the functions cooperate, as determined by the architecture, to
perform the task(s) required;
the number of replications available of each function, as determined by the way in
which the system modules provide these functions and how these functions are allocatedwithin the modules.
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1069-3 © IEC:1996 – 17–
The way in which the individual functions are set up and combined to perform tasks can
impose interdependent limits on each function. It can also impose limits on the simultaneoususe of separate functions when there is sharing of system resources.
The coverage of the system should be quantified as a coverage factor with reference to the
totality of tasks required by the system mission. If appropriate, partial coverage factorsshould be expressed for each individual task.
Configurability is dependent upon the architecture of the system and the ease with which
modules can be selected, set up, arranged and combined to assemble functions to performindustrial-process measurement and control tasks.
In practice the activity of configuring a system may require deep knowledge of system
architecture, module behaviour and module interfaces. The need for this knowledge can bereduced by the presence of configuration facilities.
Facilities for configuration can be available at any level of the system. Methods to supportthese facilities are shown in figure 3.
— Connecting by soldering
— Setting parameters
— Connecting by wiring
— Selecting options
— Setting switches
—Inserting printed circuit cards
— Inserting software modules
— Inserting modules
Figure 3 – Configuration methods
The configuration facilities are part of the system and considered as "supporting functions" ifthey are fully described in the system specification document.
Depending on the system mode of operation ("on-line", "off-line", etc.) some of the
configuration actions may or may not be permissible. Some actions (such as module set-up,
changes to module connections, module insertion or removal, etc.) may only be possiblewhilst the system is disabled from process operation.
It is also important to bear in mind that configuration changes can modify system propertiesunexpectedly.
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1069-3 © IEC:1996 –
Configurability cannot be quantified as a number. It can be described in a qualitative manner
by detailing configuration actions and tools, and stating for each of these the know-how,skills and time required.
The flexibility of a system depends on the way the system can be expanded, extended andenhanced.
Flexibility is present when it is possible to add, remove, change and/or rearrange systemmodules.
Flexibility cannot be expressed by a single measure.
A system can be designed in such a way, that it is possible to scale its size, such as byadding or removing system modules.
The extent to which the system can be scaled can be assessed by analysis of architecture,communication functions and shared resources.
Scaleability can be expressed by a qualitative description containing some quantifiedelements.
A system may be designed in such a way that it is possible to vary the range of executabletasks.
Variability can be assessed by analysis of the architecture, the degree of modularity, the
definition of interfaces between the modules and the number and scope of functionsprovided by the individual modules.
Variability can be expressed by a qualitative description containing some quantifiedelements.
A system may be designed in such a way that it is possible to enhance certain systemproperties.
Enhanceability can be assessed by analysing the architecture and the range of availablemodules with alternative property values.
Some examples are:
modules with a larger main memory to allow a decrease in response time via reduceddata transfers;
modules which allow an increased number of iterations of mathematical procedures toincrease the accuracy of a calculated value;
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1069-3 © IEC:1996 – 21 –
– use of better protected input or output cards against electrical noise to increase the
system's security, or to increase the system's usability in areas where there areexplosion hazards.
The potential for improvement of these properties can extend beyond the requirementsstated in the system requirements document.
Enhanceability can be expressed by a qualitative description containing some quantifiedelements.
5 Review of system requirements document (SRD)
The system requirements document should be reviewed to check that all the tasks to be
performed by the system and the functionality requirements have been addressed, and arelisted as described in IEC 1069-2.
The effectiveness of the functionality assessment is strongly dependent upon the
comprehensiveness of the statement of requirements.
Particular attention should be given to checking that the required configuration facilities and
the future requirements for the system have been stated and appropriately quantified, both
in relation to individual tasks as well as in relation to the total system mission.
Annex A gives guidance on the type of information the system requirements documentshould give to enable the functionality properties to be assessed.
6 Review of system specification document (SSD)
The system specification document should be reviewed to check that the functions of thesystem to perform the required tasks are listed as described in IEC 1069 -2.
Particular attention should be paid to check that information is given on:
– the system modules and elements, both hardware and software, supporting each
– quantitative and/or qualitative data on the properties of these modules and elements,and the availability of modules and elements with alternative properties;
– details of configuration tools, their use and constraints on the system operation;
– facilities provided by the system which, in the assembled operational system, support
analysis of functionality properties. Examples of these facilities are utilities forlisting all loaded programs, the supporting modules and elements;
– calculation of the spare capacity on memories devices, etc.;
– statistical analysis of system resource utilisation, etc.;
– listing any side-effects on any of the other system properties, which can occur dueto changes to the system.
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IEC:1996 – 23 –
7 Assessment procedure
The assessment should follow the procedure as laid down in clause 7 of IEC 1069-2.
The objective of the assessment shall be clearly stated. Guidance is given in 4.1 of IEC 1069-1.
The information given in the SRD and the SSD should be complete and precise to enablethe assessment of the functionality.
If at any phase of the assessment information is missing or incomplete, the originators ofthe SRD and SSD should be consulted with specific