National foreword

This British Standard is the UK implementation of EN IEC 62881:2018. It is identical to IEC 62881:2018, incorporating corrigendum April 2019.

The UK participation in its preparation was entrusted to Technical Committee GEL/65, Measurement and control.

A list of organizations represented on this committee can be obtained on request to its secretary.

This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.

Compliance with a British Standard cannot confer immunity from legal obligations.

This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 November 2018.

FOREWORD

The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International, governmental and non-governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international consensus of opinion on the relevant subjects since each technical committee has representation from all interested IEC National Committees.
IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user.
In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently to the maximum extent possible in their national and regional publications. Any divergence between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any services carried out by independent certification bodies.
All users should ensure that they have the latest edition of this publication.
No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and members of its technical committees and IEC National Committees for any personal injury, property damage or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications.
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.
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 62881 has been prepared by IEC technical committee 65: Industrial-process measurement, control and automation.

The text of this standard is based on the following documents:

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 stability date indicated on the IEC website 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.

The contents of the corrigendum of April 2019 have been included in this copy.

IMPORTANT — The 'colour inside' logo on the cover page of this publication indicates that it contains colours which are considered to be useful for the correct understanding of its contents. Users should therefore print this document using a colour printer.

INTRODUCTION

Efficient engineering and reliable operation of automated plants strongly depend on clear and unambiguous description of regulatory controls and logic interlocks. For regulatory controls this description can typically be done for example via process flow diagrams and P&IDs (ISO 10628), which are accepted by process and I&C staff in engineering and operation of manufacturing and process plants. Regarding logic interlocks the widely distributed logic or functional diagrams are very often regarded by process engineers and plant operators as too complex (especially when using the fail-safe principle) and overloaded with detailed information.

This document describes a simple and widely accepted method to document logic interlocks in process and manufacturing industries – the "cause and effect matrix" (C&E matrix). C&E matrices can be applied with minimal previous knowledge and easy handling to describe the functions required for controlling a process independently from the automation platform used. They enable a sound understanding of the required relation from a process point of view without the need of detailed knowledge of the platform specific corresponding PLC/DCS program logic.

During the entire life cycle of a plant (e.g. engineering, commissioning, start-up and operation) C&E matrices are very useful to illustrate the functionalities of package units and their interfaces to related sections of the plant. In particular they support the fulfilment of legal or insurance requirements (e.g. governmental regulations, fire and gas regulations, machinery directives such as IEC 62061). It is possible to find C&E matrices included in other types of documents, for example fire protection datasheets but still the principle of identification of the cause and the effects and their logical relations defined in an intersection applies.

In addition, they can be used to illustrate the consequences of embedded diagnostic functions (e.g. activation of a trip function in case of detection of a broken wire), the functionality of installed back-up systems (e.g. fail to start a pump and switch over to a second one) or the required operator actions to reset plant sections or safety related functions after partial shut downs.

The information presented by C&E matrices might be structured according to the individual needs, for example information necessary for process interlocks in electrical switch gears.

C&E matrices describe the relationship between causing conditions – the causes – and the required outcome or actions – the effects. The causes are herein represented by signals created by sensors or other means of information; effects are actions automatically done by actuators (mainly valves and motors) or manually by shift operators, or alarms and messages provided to operators. Both are linked via a matrix containing the relations. These basic relations are hence documented in an appropriate and structured form enabling a reliable information exchange at the interface between process design, electrical engineering, I&C engineering, etc. In the further course of detail engineering C&E matrices are used as a starting point for the development of more detailed and platform specific (e.g. fail-safe PLC) logic enhancements.

During plant operation the C&E matrices can serve as functional descriptions, for example for the training of plant operation staff.

However, C&E matrices typically are not designed to specify functional sequences (e.g. batch mode of operation) or functional details as might be provided by other methods, for example logic descriptions complying with IEC 61131‑3.

This European Standard was approved by CENELEC on 2018-11-14. 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 CEN-CENELEC Management Centre 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 CEN-CENELEC Management Centre has the same status as the official versions.

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

European foreword

The text of document 65/701/FDIS, future edition 1 of IEC 62881, prepared by IEC/TC 65 "Industrial-process measurement, control and automation" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as EN IEC 62881:2018.

The following dates are fixed:

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.

Endorsement notice

The text of the International Standard IEC 62881:2018 was approved by CENELEC as a European Standard without any modification.

In the official version, for Bibliography, the following notes have to be added for the standards indicated:

1 Scope

This document addresses the setting and implementation of C&E matrices for a consistent use in engineering activities. It aims to describe a simple format used to support a consistent exchange of information between different engineering disciplines involved in project or maintenance activities. The document defines the minimum requirements of the C&E matrix content, which is derived from existing design documents, for example P&ID or verbal descriptions.

The transfer of the relations defined in C&E matrices into a functional or source code for the application programming of PLC/DCS is out of the scope of this document. In addition, this document does not cover the implementation of complex and/or sequential logics at a dedicated automation platform, which will require additional stipulations to be done/ followed.

It is understood, that C&E matrices in fact can be used to document the fault reactions of the plant equipment and therefore can be used as reference point for the necessary safety verifications to be applied.

C&E matrices as defined in this document do not have the same scope as Fishbone or Ishikawa diagrams, which are often named in the literature as cause and effect diagrams.

2 Normative references

3 Terms, definitions and abbreviated terms

3.1 Terms and definitions

3.2 Abbreviated terms

4 Conformity

5 Design of C&E matrices

5.1 Layout principles

5.2 Attributes of causes

5.3 Attributes of effects

5.4 Attributes of relations

5.5 Marking of changes and modifications

6 Use of C&E matrices

6.1 Uniform, interdisciplinary access to functional description

6.2 Application for linear logic

6.3 Application for non-linear logic

6.4 Project workflow

7 Examples

7.1 C&E matrix with minimum requirement for cause and effect, and alternative 1 for relations

7.2 C&E matrix with minimum requirement for cause and effect, and alternative 2 for relations

7.3 C&E matrix with optional attributes for cause and effect, and alternative 2 for relations

Bibliography

BS EN IEC 62881:2018

Cause and Effect Matrix

Current

Published:

31 Jul 2019