IEC 61772:2009
(Main)Nuclear power plants - Control rooms - Application of visual display units (VDUs)
Nuclear power plants - Control rooms - Application of visual display units (VDUs)
IEC 61772:2009 supplements IEC 60964 and presents design requirements for the application of VDUs in main control rooms of nuclear power plants. Assists the designer in specifying VDU applications including displays on individual workstations and larger displays for group-working or distant viewing. The main technical changes with respect to the previous edition are as follows:
- expand the previous text to cover the use of large screen displays, to provide improved recommendations on the use of colour, and to improve the coverage of back-fit or upgrade applications;
- present examples of good practice.
Centrales nucléaires de puissance - Salles de commande - Utilisation des unités de visualisation
La CEI 61772:2009 complète la CEI 60964 et présente des exigences de conception pour l'application des unités de visualisation dans les salles de commande principales des centrales nucléaires de puissance. Aide le concepteur à spécifier les applications relatives aux unités de visualisation y compris les affichages sur les stations de travail individuelles ou sur de plus grands dispositifs d'affichage destinés au travail de groupe ou à la visualisation à distance. Les principaux changements techniques par rapport à l'édition précédente sont les suivants:
- étendre le domaine pour couvrir l'utilisation des grands écrans, et pour améliorer les recommandations concernant l'utilisation des couleurs ainsi que la couverture des applications de rénovation ou de mise à niveau;
- présenter des exemples de bonnes pratiques.
General Information
Standards Content (Sample)
IEC 61772 ®
Edition 2.0 2009-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Nuclear power plants – Control rooms – Application of visual display units
(VDUs)
Centrales nucléaires de puissance – Salles de commande – Utilisation des
unités de visualisation
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IEC 61772 ®
Edition 2.0 2009-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Nuclear power plants – Control rooms – Application of visual display units
(VDUs)
Centrales nucléaires de puissance – Salles de commande – Utilisation des
unités de visualisation
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
X
CODE PRIX
ICS 27.120.20 ISBN 978-2-88910-573-1
– 2 – 61772 © IEC:2009
CONTENTS
FOREWORD.4
INTRODUCTION.6
1 Scope and object.8
2 Normative references .9
3 Terms, efinitions and abbreviations .9
4 Design requirements .10
4.1 Intended purpose and application.10
4.1.1 General .10
4.1.2 Number and location of displays .11
4.1.3 Placement to avoid daylight and lighting problems.12
4.2 Principal users .13
4.3 Failure criteria .14
4.4 System requirements.14
4.5 Information needs and application procedures.15
4.5.1 General .15
4.5.2 Back-fitting applications.16
4.5.3 New MCR design.16
5 Design and implementation of VDU formats.17
5.1 Design.17
5.2 General requirements.18
5.2.1 Presentation .18
5.2.2 Availability.18
5.2.3 Legibility.18
5.3 Accuracy .19
5.3.1 Understandability.19
5.3.2 Compatibility of VDU-formats with other man-machine interfaces .19
5.3.3 Consistency between VDU formats.19
5.4 Form of presentation .20
5.4.1 Principles .20
5.4.2 Use of symbols and graphics .21
5.4.3 Schematic and mimic displays .21
5.4.4 Formatting of information.21
6 Design and implementation of large screen displays.22
6.1 Purpose of LSD systems .22
6.2 Overview of LSD design issues .23
6.3 Placement of LSDs in the MCR .23
6.3.1 General .23
6.3.2 Placement relative to operators’ viewing areas .24
6.4 Information-content of LSD formats .25
6.4.1 General .25
6.4.2 Screen and display performance.26
6.4.3 Screen format design for LSDs .26
6.4.4 Special colour issues for LSD formats .27
6.5 Control of change of display-content on LSDs .28
7 Verification .29
8 Validation .29
61772 © IEC:2009 – 3 –
Annex A (informative) Advantages and disadvantages of VDU-based display .30
Annex B (informative) Examples of formats, typical use and some characteristics .32
Annex C (informative) Format design and implementation basis .34
Annex D (informative) Examples of access methods .35
Annex E (informative) Verification and validation of VDU .36
Annex F (informative) Method of VDU format design presenting information on plant
conditions and equipment state.39
Figure E.1 – Format creation and verification.38
– 4 – 61772 © IEC:2009
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
NUCLEAR POWER PLANTS – CONTROL ROOMS –
APPLICATION OF VISUAL DISPLAY UNITS (VDUs)
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
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2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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6) All users should ensure that they have the latest edition of this publication.
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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 61772 has been prepared by subcommittee 45A: Instrumentation
and control of nuclear facilities, of IEC technical committee 45: Nuclear instrumentation.
This second edition cancels and replaces the first edition published in 1995 and constitutes a
technical revision.
The main technical changes with respect to the previous edition are as follows:
– Expand the previous text to cover the use of Large Screen Displays (LSDs), to provide
improved recommendations on the use of colour, and to improve the coverage of back-fit
or upgrade applications.
– Provide references to relevant normative standards.
– Harmonise terminology according to SC 45A guidance.
– Cover experience of VDU systems design and use.
– Present examples of good practice, including methods of access to displays of current
interest.
61772 © IEC:2009 – 5 –
The text of this standard is based on the following documents:
FDIS Report on voting
45A/728/FDIS 45A/740/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.
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.
– 6 – 61772 © IEC:2009
INTRODUCTION
a) Technical background, main issues and organisation of this Standard
During the work to create a standard for the design of control rooms of nuclear power plants,
it became obvious that the volume of such a standard would become very large. Therefore the
standard was split into one main standard (IEC 60964 with an annex) and some
supplementary standards. This standard is one of the supplementary standards.
It is intended that the Standard be used by operators of NPPs (utilities), designers, systems
evaluators and by licensors.
b) Situation of this Standard in the structure of the IEC SC 45A standard series
IEC 61772 is the third level IEC SC 45A document tackling the generic issue of use of VDUs
in NPPs Main Control Room.
IEC 61772 is to be read in conjunction with IEC 60964 which is the appropriate IEC SC 45A
document which provides general requirements concerning the design of Nuclear Power
Plants main control rooms. IEC 61227, IEC 61771, IEC 62241 and IEC 61839 should also be
read with this standard.
For more details on the structure of the IEC SC 45A standard series, see item d) of this
introduction.
c) Recommendations and limitations regarding the application of this Standard
It is important to note that this Standard establishes no additional functional requirements for
safety systems.
To ensure that the Standard will continue to be relevant in future years, the emphasis has
been placed on issues of principle, rather than specific technologies.
d) Description of the structure of the IEC SC 45A standard series and relationships
with other IEC documents and other bodies documents (IAEA, ISO)
The top-level document of the IEC SC 45A standard series is IEC 61513. It provides general
requirements for I&C systems and equipment that are used to perform functions important to
safety in NPPs. IEC 61513 structures the IEC SC 45A standard series.
IEC 61513 refers directly to other IEC SC 45A standards for general topics related to
categorization of functions and classification of systems, qualification, separation of systems,
defence against common cause failure, software aspects of computer-based systems,
hardware aspects of computer-based systems, and control room design. The standards
referenced directly at this second level should be considered together with IEC 61513 as a
consistent document set.
At a third level, IEC SC 45A standards not directly referenced by IEC 61513 are standards
related to specific equipment, technical methods, or specific activities. Usually these
documents, which make reference to second-level documents for general topics, can be used
on their own.
A fourth level extending the IEC SC 45 standard series, corresponds to the Technical Reports
which are not normative.
IEC 61513 has adopted a presentation format similar to the basic safety publication
IEC 61508 with an overall safety life-cycle framework and a system life-cycle framework and
61772 © IEC:2009 – 7 –
provides an interpretation of the general requirements of IEC 61508-1, IEC 61508-2 and
IEC 61508-4, for the nuclear application sector. Compliance with IEC 61513 will facilitate
consistency with the requirements of IEC 61508 as they have been interpreted for the nuclear
industry. In this framework IEC 60880 and IEC 62138 correspond to IEC 61508-3 for the
nuclear application sector.
IEC 61513 refers to ISO as well as to IAEA 50-C-QA (now replaced by IAEA GS-R-3) for
topics related to quality assurance (QA).
The IEC SC 45A standards series consistently implements and details the principles and
basic safety aspects provided in the IAEA code on the safety of NPPs and in the IAEA safety
series, in particular the Requirements NS-R-1, establishing safety requirements related to the
design of Nuclear Power Plants, and the Safety Guide NS-G-1.3 dealing with instrumentation
and control systems important to safety in Nuclear Power Plants. The terminology and
definitions used by SC 45A standards are consistent with those used by the IAEA.
– 8 – 61772 © IEC:2009
NUCLEAR POWER PLANTS – CONTROL ROOMS –
APPLICATION OF VISUAL DISPLAY UNITS (VDUs)
1 Scope and object
This International Standard supplements IEC 60964. It presents design requirements for the
application of VDUs in main control rooms of nuclear power plants.
For the main control room of a nuclear power plant, IEC 60964 includes general requirements
for layout, user needs and verification and validation methods and these aspects are not
repeated in this standard. IEC 61227, IEC 61771, IEC 62241 and IEC 61839 should also be
read with this standard.
This standard assists the designer in specifying VDU applications (including displays on
individual workstations and larger displays for group-working or distant viewing) together with
or instead of conventional (panel) displays by:
– stating principles to take advantage of VDU capability;
– giving examples of good practice and guiding the designer to avoid deficiencies of design.
This standard contains:
a) requirements for information needs:
– according to information goals e.g. operation, maintenance, protection,
– allowing for the necessary amount of space, e.g. location, arrangement,
– using a hierarchy and/or relationships,
– avoiding unnecessary information,
– ensuring that information is relevant,
b) requirements for good presentation such as:
– clear and flicker-free display with suitable updating frequency,
– enough display space and an optimal arrangement,
– adequate format and symbol sizes,
– pictorial, symbolic display in addition to alpha-numeric capacity,
– standardized, common symbols and names,
– arrangements oriented to human factor needs, e.g. population stereotypes,
– use of grouping and coding methods,
– use of consistent flow directions,
– appropriate abstraction levels according to the needs of the different presumed users,
c) methods for easy and quick access to the specific information of current interest:
– by simple selection of single formats or format-sets according to information goals,
– by using different kinds of menus (icons of neighbouring information) or other access
techniques (last display, selection on screen, etc.) by soft keys on or off the VDU
screens or cursors,
– by using programmed presentation (triggered by any binary signal, such as an alarm),
d) design criteria to obtain appropriate reliability of all functions necessary to achieve the
specified information goals.
61772 © IEC:2009 – 9 –
This standard is intended for application to the design of new main control rooms in nuclear
power plants designed to IEC 60964 and where this is initiated after the publication of this
standard. If it is to be applied to existing control rooms or control areas designs, care should
be taken as some assumptions made (such as automation level) may not apply.
Where a deviation from this standard is necessary in a back-fitting application the reasons
should be documented.
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 60964:2009, Nuclear power plants – Control rooms - Design
IEC 61226:2005, Nuclear power plants – Instrumentation and control systems important to
safety – Classification of instrumentation and control functions
IEC 61227:2008, Nuclear power plants – Control rooms – Operator controls
IEC 61513, Nuclear power plants – Instrumentation and control for systems important to
safety – General requirements for systems
IEC 61771, Nuclear power plants – Main control room – Verification and validation of design
IEC 61839:2000, Nuclear power plants – Design of control rooms – Functional analysis and
assignment
IEC 62241:2004, Nuclear power plants – Main control room – Alarm functions and
presentation
ISO 11064 (all parts), Ergonomic design of control centres
IAEA Safety Guide NS-G-1.3:2002, Instrumentation and control systems important to safety in
Nuclear Power Plants
3 Terms, definitions and abbreviations
For the purposes of this document, the terms, definitions and abbreviations given in
IEC 60964 apply as well as the following:
3.1
associated information
additional, or helpful information complementary to the main display content of a single format
or a format-set. The existence of this additional capability of display may be indicated by
certain icons (navigation targets, as integrated parts of the displayed information) and their
selection will lead to the display of single formats or pictorial menus or, where suitable, alpha-
numeric menus
3.2
Large Screen Display (LSD)
any form of larger display intended for group viewing, shared tasks, monitoring at a distance,
etc.
– 10 – 61772 © IEC:2009
3.3
navigation targets
areas on the display screens that provide access to other displays, when a cursor or pointer is
placed on the area and a suitable control action is taken
3.4
primary display
VDU display intended as the main (or one of the main) displays to facilitate the operator’s
main monitoring and control tasks. Primary displays need to be located more restrictively so
that the operator is able to use them effectively from the working position
3.5
secondary display
VDU display filling a supportive role, such as to promote general situation awareness, group
cooperation, casual monitoring when moving around the MCR, overall monitoring when not
occupied with more specific tasks
3.6
touch panel
soft control which uses a position detector to detect the operator's finger pointing at the label
on the VDU. Alternatively, a light pen may be used or a cursor may be moved over the VDU
format to identify a label. The label may describe an item of plant or a control action.
3.7
Visual Display Unit (VDU)
type of display incorporating a screen for presenting computer-driven images
[IEC 60964]
3.8 Abbreviations
CRT: cathode ray tube
DLP: digital light processing
LCD: liquid crystal display
LSD: large-screen display
MCR: main control room
NPP: nuclear power plant
V&V: verification and validation
VDU: visual display unit
4 Design requirements
4.1 Intended purpose and application
4.1.1 General
The design process of the VDU system shall reflect the requirements of IEC 60964.
The design process shall identify the goals of the display system, e.g. safety, availability,
operability.
61772 © IEC:2009 – 11 –
Where a system is back-fitted to an existing plant, the extent of application of the
requirements of IEC 60964 and of this standard shall be identified.
The availability requirements shall be determined from the classification of the system in
accordance with IEC 61226 and IEC 61513.
The VDU system shall be designed so that operators can perform their tasks correctly and
promptly. Account should be taken of the relationship between the information to be
presented and any associated controls.
Consideration shall be given to control/display integration and the type of operating procedure
(event based, symptom-based or state-based).
The presentation of the relevant information shall be taken into account in the choice of the
kind of display to be used.
The design shall be based on ergonomic principles to ensure ease of operation and to
minimize operator errors, both of intention and execution.
As the information displayed on VDUs is a major information source and contributes to the
total operator workload, the display design shall minimize the workload contribution from
monitoring, operation and problem solving to avoid information overload.
The design of the VDU system shall develop and document a clear definition of the intended
purpose of the displays, their safety role and their basic performance requirements.
The following factors have great influence on the necessary extent, structure and capabilities
of the entire system:
– new design or back-fitting application,
– safety, non-safety or legal licensing relevance,
– extent of plant automation,
– capabilities and needs of the main users,
– display only, or integrated soft controls.
The system may be provided in one step or in several steps according to funding, time limits,
increased experience or changes in the state of the art of hardware and software, and
changes in philosophies which might affect the role of the operators.
Some aspects of enhanced VDU-based displays are given in Annex A of this standard.
This standard offers broad guidance, but when the project needs to go into more detail, a set
of specific design and style guides shall be established. To do so, this standard also provides
directions to ensure that the project specific guidance can provide a consistent design across
displays, systems and old/new equipment.
4.1.2 Number and location of displays
Typically, one of the first design decisions is the overall control-room configuration, i.e.:
– number and location of computer workstations and their hardware such as VDUs,
keyboards,
– number and location of other hardware items such as alarms and controls.
In order to minimize late changes of the design, an early analysis of operator tasks should
include the following tasks:
– 12 – 61772 © IEC:2009
– analysing the information to be presented to the operators,
– obtaining input from operating crews.
For new plant designs the following should be included in the design team:
– staff with operating experience from previous plants,
– staff with operating experience from similar designs,
– representative future operators.
Determining the appropriate amount of display area should include consideration of:
– the information that will be needed at one time by the operators,
– the arrangement of information within display pages,
– the arrangement of pages within the display network,
– the means used to access the information.
The coordination of activities among crew members should be taken into account.
4.1.3 Placement to avoid daylight and lighting problems
The overall requirements and guidance given in the general control room design basis are
relevant.
The major lighting problem is to supply enough light to illuminate printed and written material
without illuminating the display screens (and LSDs) and undesirably reducing screen contrast.
In general, the overall lighting in the control room should be indirect and somewhat diffuse.
The room décor and colours of furnishing are important in determining the overall appearance
of the workspace.
Architectural-surface reflectance should support diffuse lighting while not creating too much
reduction of contrast on VDUs and LSDs.
The lighting scheme and choice of luminaires should be integrated with the rest of the design
process.
The lighting scheme and choice of luminaires should not be handled piecemeal or in isolation.
Each new light-source or bright surface that is added into a control-room can potentially
cause a variety of problems. For example:
– unplanned supplementary illumination can cause glare or reflections from VDU screens;
– unplanned general lighting can cast “waste light” or scattered light onto LSDs, reducing:
– contrast,
– colour-saturation,
– readability.
Note that projection-screens with lower gain are more prone to cause the above problems
than screens with higher gain.
Windows that admit daylight are especially problematic for LSDs.
Light distribution may need to be carefully controlled.
61772 © IEC:2009 – 13 –
Front-projectors should be positioned so that they do not cause glare or reflections on
operator workstation displays.
Care should be taken with colours in relation to room lighting conditions. Note that:
– unsaturated colours are difficult to discriminate in bright room light,
– similar colours are hard to distinguish in dim room-lighting.
Luminaires should have neutral colour rendering.
Coloured ambient illumination should not be used if colour-coding is used in the control-room.
Lamp-types with poor colour-rendering should not be used.
If the control-room has emergency lighting that may be used while operators continue to use
displays, then this also should have good colour-rendering
4.2 Principal users
The principal users of each group of VDUs shall be identified as part of the definition of
design requirements. These may be the reactor or other plant operators, the operation
supervisor, maintenance staff or management. In the case of LSDs, there may be different
users or groups of users situated in different areas of the MCR.
The level of understanding of the displayed information shall be primarily related to main
control room operators’ mental capabilities and the formats shall be produced with their fullest
co-operation from the outset. This is because operators in the main control room normally are
the principal users of the information system at NPPs in normal, disturbed and accident
situations. They are the only personnel always present and in charge.
In addition to the basic information, a more concentrated and abstract display of information
shall be given to shift leaders, safety engineers and, according to utility practice, other on-site
and off-site advisors to the control room staff. These may be concerned with the analysis and
strategic decision-making in longer lasting, complex situations. Such a display format is also a
suitable candidate for LSD when one of its identified functions is to maintain situation
awareness and promote group cooperation.
The design targets should be to enhance the operators' role towards that of a safety and
performance optimizer, by exploiting and supporting the mental capacity and expert
knowledge of the operator.
Experience of display use on nuclear plants shows that operating and maintenance staff need
access to all plant information, both direct and derived, within the workstation’s VDU display
system, and that this should include specific facilities to allow display of information on:
– logic control algorithms,
– trip setpoints,
– alarm thresholds,
– signal scale factors,
– input assignment,
and other characteristics of the system used to define the performance of the display
application. This facility is of specific value during plant commissioning and for the
confirmation of modifications.
– 14 – 61772 © IEC:2009
4.3 Failure criteria
The reliability requirements and failure criteria should be identified from the safety
categorization process of IEC 61226 and from plant safety requirements, emerged from,
among others, regulatory bodies. A failure of an information system means that the
information is degraded and not sufficient and precise enough to understand or perform a
safety task properly. A single failure within a system is any failure of a component, e.g., a
sensor, a processor or a display unit.
Applications of VDUs may include:
a) Individual screens and LSDs with no safety relevance and other instruments, used to
enhance the understanding of certain situations or to facilitate early detection of
abnormalities such as those which inform about actions of automatic systems, energy or
fluid flows and balances and small radioactivity releases or leakage.
b) LSDs and screens for information and control which may have safety relevance such as
those necessary to perform actions according to safety-related procedures for plant
conditions within and beyond the design bases.
c) Screens for safety such as those of a dedicated safety panel.
d) Soft controls in an integrated information and control system.
Such applications may be used for new designs or back-fitting of control rooms.
For case a),
– Redundancy is generally not essential and an occasional failure of the information function
may be acceptable.
For case b),
– Redundancy shall be provided to ensure that a single component failure in the system
does not prevent operation of its general function.
– Display functions (consisting of already concentrated information) should have an
availability which meets the relevant documented safety needs.
For case c),
– A failure of a single display shall not prevent operator actions required for safety.
Redundancy and diversity of information and control means may be used for this.
– Information necessary for handling accidents shall rely only on safety qualified
measurements of sufficient redundancy but may be supplemented by other information.
– The probability of a failure of the information function shall be considered in relation to the
relevant and documented safety needs.
For case d),
– A failure of a single display shall be considered according to the safety and availability
criteria of a), b) or c), for which the control actions concerned are taken.
4.4 System requirements
Subclauses 4.1 to 4.3 enable the designer to determine requirements for the VDUs. This
document states the high level requirements.
A style guide should give detailed guidance on specific response time, viewing angle limits
etc.
The following areas shall have detailed requirements developed:
61772 © IEC:2009 – 15 –
– the amount and structure of computing and storage capability,
– the necessary redundancy, diversity and complexity of information,
– the environmental conditions and requirements for the VDU or LSD.
Requirements intended primarily for workstation VDU-system design shall be established for
the following:
– the character and symbol sizes provided by the VDU equipment,
– the number of sufficient pixels to differentiate the symbols employed where a character
matrix is used,
– specific requirements for the maximum viewing angle for a primary or a secondary display
(between the line of sight and the perpendicular to the plane of the display),
– specific requirements for the contrast of characters and symbols to background with
possible control of luminance,
– the update frequency of information in digital form.
In addition the following requirements are fixed for workstation VDU-system design:
– The call-up time of any element of a format (set) shall meet the needs for display
presentation arising from task analysis.
– The call-up time of any element of a format (set) shall meet the operator's human factor
needs for display.
– The update frequency of information in digital form should be one that ensures that data is
easily and accurately read by the operator, whether the plant is at steady-state or in a
transient, and without rapidly changing lowest digits being displayed.
– The character and symbol sizes provided by the VDU equipment should be sufficient for
human factors recommendations on legibility.
Requirements for the VDUs themselves shall be established and include:
– the colours used to code information,
– the screens refresh frequency,
– the spectrum of installed room lighting,
– the phosphor persistence of CRT-type VDUs. Special considerations may apply for other
technologies, such as LCD, DLP.
In addition the following requirements are fixed for the VDUs themselves:
– Flashing of text or variables shall be avoided.
– Suitable measures shall be provided to ensure the reflection of other light sources on the
screens are kept to a level that does not interfere with task performance or cause
discomfort.
– Soft controls shall have a feedback mechanism providing information on whether the
action called for has been executed or not. Critical actions shall be protected from
accidental activation.
Further details about soft controls are given in IEC 61227.
4.5 Information needs and application procedures
4.5.1 General
The information to be displayed shall be defined in principle and then in detail by analysis of
the operators' and other users' needs for information in different operating conditions.
The design process should include review and comment by experienced operators.
– 16 – 61772 © IEC:2009
Screen formats should “use the user’s model”. The industry and even sub-populations in it will
have their own associations and well-learnt meanings for e.g.:
– piping,
– fluids,
– alarm status.
User’s models may also depend on the plant’s and operators history with previous equipment
and traditional panels. There is therefore no automatic need to completely redesign displays
from effective conventional panels simply because the displays will now be realised with LSD
technology.
The user’s “model” is built up from:
– education,
– training, and
– operational experience.
The user’s “model” includes knowledge of:
– the connections between plant systems, allowing deductions of how fluids can get from
one system to another;
– mass and energy changes in a system, allowing the prediction of the effect on a second
system.
4.5.2 Back-fitting applications
The addition of VDUs or substitution of conventional instrumentation by VDUs may enable
information to be presented that cannot easily and simply be displayed by conventional
instruments, particularly where flexibility is required in a display, for example:
– the output of computer calculations and comparisons,
– overview displays based on derived values, grouped alarms, trends, synthesized variables
to summarise plant state, etc.,
– x-y diagrams (graphs of a value against another value), e.g. safety parameters or critical
functions display,
– x-t diagrams (graphs of value against time),
– trend logs with flexible scaling (also for long-term history),
– system mimic diagrams with real time status information,
– combinations of different information, e.g. a core map on four screens,
– operating procedures with real time status information.
4.5.3 New MCR design
An iterative procedure should be followed that encompasses:
a) investigation and specification of the main objectives (top-down approach), such as:
– information goals for monitoring of the plant and the automatic actions,
– information for decision-making (for manual actions),
b) collation of display requirements for status and trend information of plant conditions and
automatic control systems including protection systems (bottom-up approach);
c) determination of the relationship between display formats.
This should take into account:
– associated formats,
61772 © IEC:2009 – 17 –
– related information,
– different views formats;
d) refinement of the design by repeating these design steps and adding more details.
Examples of different formats, their typical use and some of their characteristics are given in
Annex B.
5 Design and implementation of VDU formats
5.1 Design
A system based approach to functional design of the control room shall be used to determine
the information and control needs of the assumed users (see IEC 60964, clause 6 and
IEC 61839).
A new design for a general control suite arrangement should identify:
– a list of system functions in the MCR,
– information on work-tasks in the MCR,
– information on the tasks to be undertaken by those outside the MCR who can easily see
into the MCR,
– a preliminary description of the equipment to be installed in the MCR.
In the case of a retrofit, redesign, or upgrade a review of current work-tasks and an analysis
of the constraints to be observed shall be done when proposing changes to the way work is
done.
The requirem
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