EN 61987-11:2017

SLOVENSKI STANDARD
01-september-2017
1DGRPHãþD
SIST EN 61987-11:2012
Merjenje in nadzor industrijskega procesa - Strukture podatkov in elementi v
katalogih procesne opreme - 11. del: Seznam lastnosti merilne opreme za
elektronsko izmenjavo podatkov - Splošne strukture (IEC 61987-11:2016)
Industrial-process measurement and control - Data structures and elements in -process
equipment catalogues - Part 11: Lists of properties (LOPs) of measuring equipment for
electronic data exchange - Generic structures (IEC 61987-11:2016)
Industrielle Leittechnik - Datenstrukturen und -elemente in Katalogen der
Prozessleittechnik - Teil 11: Merkmalleisten (ML) für Messgeräte für den elektronischen
Datenaustausch - Allgemeine Strukturen (IEC 61987-11:2016)
Mesure et commande des processus industriels - Structures de données et éléments
dans les catalogues d'équipement de processus - Partie 11: Listes des propriétés (LOP)
d'équipements de mesure pour l'échange électronique de données - Structures
génériques (IEC 61987-11:2016)
Ta slovenski standard je istoveten z: EN 61987-11:2017
ICS:
01.110 7HKQLþQDGRNXPHQWDFLMD]D Technical product
L]GHONH documentation
25.040.40 Merjenje in krmiljenje Industrial process
industrijskih postopkov measurement and control
35.240.50 Uporabniške rešitve IT v IT applications in industry
industriji
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 61987-11

NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2017
ICS 25.040.40; 35.100.20 Supersedes EN 61987-11:2012
English Version
Industrial-process measurement and control - Data structures
and elements in -process equipment catalogues - Part 11: Lists
of properties (LOPs) of measuring equipment for electronic data
exchange - Generic structures
(IEC 61987-11:2016)
Mesure et commande des processus industriels - Industrielle Leittechnik - Datenstrukturen und -elemente in
Structures de données et éléments dans les catalogues Katalogen der Prozessleittechnik - Teil 11: Merkmalleisten
d'équipement de processus - Partie 11: Listes des (ML) für Messgeräte für den elektronischen
propriétés (LOP) d'équipements de mesure pour l'échange Datenaustausch - Allgemeine Strukturen
électronique de données - Structures génériques (IEC 61987-11:2016)
(IEC 61987-11:2016)
This European Standard was approved by CENELEC on 2017-01-19. 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 Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2017 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 61987-11:2017 E
European foreword
The text of document 65E/467/CDV, future edition 2 of IEC 61987-11, prepared by SC 65E “Devices
and integration in enterprise systems” of IEC/TC 65 “Industrial process measurement, control and
automation" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:
• latest date by which the document has to be (dop) 2017-10-21
implemented at national level by
publication of an identical national
standard or by endorsement
(dow) 2020-04-21
• latest date by which the national
standards conflicting with the
document have to be withdrawn
This document supersedes EN 61987-11:2012.

Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such
patent rights.
Endorsement notice
The text of the International Standard IEC 61987-11:2016 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:
IEC 60770-1:2010 NOTE Harmonized as EN 60770-1:2011
IEC 61360-1:2009 NOTE Harmonized as EN 61360-1:2010
IEC 61360-2 NOTE Harmonized as EN 61360-2
IEC 61987-12 NOTE Harmonized as EN 61987-12
IEC 81346-1:2009 NOTE Harmonized as EN 81346-1:2009
ISO 10303 (Series) NOTE Harmonized as ENV 10303 (Series)

Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
NOTE 1 When an International Publication has been modified by common modifications, indicated by (mod), the relevant

EN/HD applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here:
www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60947-5-6 -  Low-voltage switchgear and controlgear -- EN 60947-5-6 -
Part 5-6: Control circuit devices and
switching elements - DC interface for
proximity sensors and switching amplifiers
(NAMUR)
IEC 61069-5 -  Industrial-process measurement, control EN 61069-5 -
and automation - Evaluation of system
properties for the purpose of system
assessment - Part 5: Assessment of
system dependability
IEC 61508-6 -  Functional safety of EN 61508-6 -
electrical/electronic/programmable
electronic safety-related systems -- Part 6:
Guidelines on the application of IEC
61508-2 and IEC 61508-3
IEC 61987-1 2006 Industrial-process measurement and EN 61987-1 2007
control - Data structures and elements in
process equipment catalogues -- Part 1:
Measuring equipment with analogue and
digital output
IEC 61987-10 2009 Industrial-process measurement and EN 61987-10 2009
control - Data structures and elements in
process equipment catalogues - Part 10:
Lists of Properties (LOPs) for Industrial-
Process Measurement and Control for
Electronic Data Exchange - Fundamentals
- -  + AC 2011
IEC 61987-92 -  - -
IEC 62424 -  Representation of process control EN 62424 -
engineering - Requests in P&I diagrams
and data exchange between P&ID tools
and PCE-CAE tools
IEC 61987-11 ®
Edition 2.0 2016-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Industrial-process measurement and control – Data structures and elements in

process equipment catalogues –

Part 11: Lists of properties (LOPs) of measuring equipment for electronic data

exchange – Generic structures
Mesure et commande des processus industriels – Structures de données et

éléments dans les catalogues d'équipement de processus –

Partie 11: Listes des propriétés (LOP) d'équipements de mesure pour l'échange

électronique de données– Structures génériques

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 25.040.40; 35.100.20 ISBN 978-2-8322-3692-5

– 2 – IEC 61987-11:2016 © IEC 2016
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 9
2 Normative references . 9
3 Terms and definitions . 10
3.1 Terms and definitions concerning measuring instruments . 10
3.2 Terms and definitions concerning relationships . 11
4 General . 13
4.1 Characterization scheme. 13
4.2 Aspects . 13
4.3 Rules for the construction of LOPs with block structure . 15
4.3.1 Block order . 15
4.3.2 Position of cardinality properties . 15
4.3.3 Naming of blocks created by cardinality . 15
4.3.4 Characterizing property . 15
4.3.5 Validity . 15
4.4 OLOP and DLOP . 15
4.5 Operating conditions . 16
4.6 Measuring equipment configuration . 17
5 Operating list of properties (OLOP) . 18
5.1 Generic block structure . 18
5.2 Base conditions . 19
5.3 Process case . 19
5.3.1 General . 19
5.3.2 Process case variables . 19
5.3.3 Other process case variable . 20
5.4 Operating conditions for device design. 20
5.4.1 General . 20
5.4.2 Installation design conditions . 20
5.4.3 Environmental design conditions. 20
5.4.4 Process design conditions . 21
5.4.5 Pressure-temperature design conditions . 21
5.5 Process equipment . 22
5.5.1 General . 22
5.5.2 Line or nozzle . 22
5.6 Physical location . 22
5.6.1 General . 22
5.6.2 Available power supply . 22
5.6.3 Process criticality classification . 23
5.6.4 Area classification . 23
6 Device list of properties (DLOP) . 23
6.1 General . 23
6.1.1 Generic block structure . 23
6.1.2 Relationship to IEC 61987-1 . 25
6.1.3 Multivariable devices . 25
6.2 Identification . 26

IEC 61987-11:2016 © IEC 2016 – 3 –
6.3 Application . 26
6.4 Function and system design . 26
6.4.1 General . 26
6.4.2 Dependability . 26
6.5 Input . 26
6.5.1 General . 26
6.5.2 Measured variable . 26
6.5.3 Auxiliary input . 27
6.6 Output. 28
6.6.1 General . 28
6.6.2 output . 29
6.7 Digital communication . 30
6.7.1 General . 30
6.7.2 Digital communication interface . 30
6.8 Performance . 30
6.8.1 General . 30
6.8.2 Reference conditions for the device . 30
6.8.3 Performance variable . 30
6.9 Rated operating conditions . 32
6.9.1 General . 32
6.9.2 Installation conditions . 32
6.9.3 Environmental design ratings . 33
6.9.4 Process design ratings . 33
6.9.5 Pressure-temperature design ratings . 34
6.10 Mechanical and electrical construction . 34
6.10.1 General . 34
6.10.2 Overall dimensions and weight . 34
6.10.3 Structural design . 35
6.10.4 Explosion protection design approval . 35
6.10.5 Codes and standards approval . 35
6.11 Operability . 35
6.11.1 General . 35
6.11.2 Basic configuration . 35
6.11.3 Parametrization . 35
6.11.4 Adjustment . 35
6.11.5 Operation . 35
6.11.6 Diagnosis . 35
6.12 Power supply . 36
6.13 Certificates and approvals. 36
6.14 Component part identifications . 36
7 Composite devices . 36
7.1 Structure of composite devices . 36
7.2 Aspects of components . 38
8 Additional aspects . 38
8.1 Administrative information . 38
8.2 Calibration and test . 39
8.3 Accessories . 39
8.4 Device documents supplied. 39
8.5 Packaging and shipping . 39

– 4 – IEC 61987-11:2016 © IEC 2016
8.6 Digital communication parametrization . 39
8.7 Example of a composite device with aspects . 39
Annex A (informative) Device type dictionary – Classification of process measuring
equipment according to measuring characteristics . 41
Bibliography . 60

Figure 1 – Characterisation of measuring equipment . 13
Figure 2 – Simplified UML scheme of device, LOPs and aspects . 14
Figure 3 – Assignment of OLOPs and DLOPs for equipment used to measure one type
of measured variable . 16
Figure 4 – Structure of a composite device . 37
Figure 5 – Example for the structure of an LOP for a composite device showing
different aspects related to different sub-components . 40

Table 1 – Structure of the block “Operating conditions for device design” in the OLOP . 17
Table 2 – Structure of the block “Rated operating conditions” in the DLOP . 17
Table 3 – Generic block structure of an OLOP . 18
Table 4 – Generic block structure of a DLOP . 24
Table 5 – DLOP structure for composite devices . 37
Table A.1 – Classification scheme for process measuring equipment . 41

IEC 61987-11:2016 © IEC 2016 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
INDUSTRIAL-PROCESS MEASUREMENT AND CONTROL –
DATA STRUCTURES AND ELEMENTS IN PROCESS
EQUIPMENT CATALOGUES –
Part 11: Lists of properties (LOPs) of measuring equipment
for electronic data exchange – Generic structures

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
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.
2) 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.
3) 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.
4) 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.
5) 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.
6) All users should ensure that they have the latest edition of this publication.
7) 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.
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 61987-11 has been prepared by subcommittee 65E: Devices and
integration in enterprise systems, of IEC technical committee 65: Industrial-process
measurement, control and automation.
This second edition cancels and replaces the first edition published in 2012. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) The classification in Table A.1 has been amended to reflect the changes in the
classification scheme of process measuring equipment in the CDD due to the development
of IEC 61987-14, IEC 61987-15 and IEC 61987-16.
b) Annex A has become “informative”.

– 6 – IEC 61987-11:2016 © IEC 2016
The text of this standard is based on the following documents:
CDV Report on voting
65E/467/CDV 65E/509/RVC
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.
A list of all parts in the IEC 61987 series, published under the general title Industrial-process
measurement and control – Data structures and elements in process equipment catalogues,
can be found on the IEC website.
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.
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.
IEC 61987-11:2016 © IEC 2016 – 7 –
INTRODUCTION
The exchange of product data between companies, business systems, engineering tools, data
systems within companies and, in the future, control systems (electrical, measuring and
control technology) can run smoothly only when both the information to be exchanged and the
use of this information has been clearly defined.
Prior to this document, requirements on process control devices and systems were specified
by customers in various ways when suppliers or manufacturers were asked to quote for
suitable equipment. The suppliers in their turn described the devices according to their own
documentation schemes, often using different terms, structures and media (paper, databases,
CDs, e-catalogues, etc.). The situation was similar in the planning and development process,
with device information frequently being duplicated in a number of different information
technology (IT) systems.
Any method that is capable of recording all existing information only once during the planning
and ordering process and making it available for further processing, gives all parties involved
an opportunity to concentrate on the essentials. A precondition for this is the standardization
of both the descriptions of the objects and the exchange of information.
This standard series proposes a method for standardization which will help both suppliers and
users of measuring equipment to optimize workflows both within their own companies and in
their exchanges with other companies. Depending on their role in the process, engineering
firms may be considered here to be either users or suppliers.
The method specifies measuring equipment by means of blocks of properties. These blocks
are compiled into lists of properties (LOPs), each of which describes a specific equipment
(device) type. This standard series covers both properties that may be used in an inquiry or a
proposal and detailed properties required for integration of the equipment in computer
systems for other tasks.
IEC 61987-10 defines structure elements for constructing lists of properties for electrical and
process control equipment in order to facilitate automatic data exchange between any two
computer systems in any possible workflow, for example engineering, maintenance or
purchasing workflow and to allow both the customers and the suppliers of the equipment to
optimize their processes and workflows. IEC 61987-10 also provides the data model for
assembling the LOPs.
IEC 61987-11 specifies the generic structure for operating and device lists of properties
(OLOPs and DLOPs). It lays down the framework for further parts of IEC 61987 in which
complete LOPs for device types measuring a given physical variable and using a particular
measuring principle will be specified. The generic structure may also serve as a basis for the
specification of LOPs for other industrial-process control instrument types such as control
valves and signal processing equipment.
Content of the lists of properties (LOPs)
The LOPs specified in this document describe at generic level:
• the operating conditions of the measuring equipment;
• the ambient conditions at the measuring point;
• the performance of the measuring equipment;
• the metrological, mechanical and electrical features of the measuring equipment;
• the compliance of the measuring instrument to specific industrial requirements.
The LOPs mirror constructive reality but do not represent an instrument model.

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Measuring equipment configuration
The generic LOPs have been so constructed that they take account of integral equipment and
separately mounted equipment.
Device type dictionary
Annex A describes a characterisation of measuring equipment based on the STEP library,
ISO 10303. This is a tree of relationships between different device types. Starting at the root
“equipment for industrial-process automation”, it first characterizes measuring equipment
according to type, then according to process variable measured and finally according to the
measuring method employed. This structure will be used in the IEC Common Data Dictionary
(CDD) “Process automation (IEC 61987 series)” domain.
For the purpose of this document, the following types of measuring equipment have been
identified, see Clause 3 for definitions:
• sight indicator (with direct indicating qualitative output),
• gauge (with quantitative output only in the form of a direct indicating display),
• transmitter (with quantitative analogue output or corresponding digital output signal),
• switch (with discrete output or corresponding digital output signal),
• measuring assembly (as a grouping of instrument components, which together form a
gauge, transmitter or switch).
It should be noted that in the real world, there is not such a clear demarcation between types
of measuring equipment. In commercial literature, indicators are often called gauges, although
the products offer no quantitative measurement. Similarly, direct indicating displays are often
equipped with electrical trip switches which allow a gauge to act as a switch. Finally
“transmitter” is by no means a universal term and in particular for flow measurement many
manufacturers call this kind of equipment “meter”.
Composite devices
A structural scheme is given, defining how to build up LOPs for devices consisting of several
components or assembled from different parts, that is, composite devices and measuring
assemblies.
IEC 61987-11:2016 © IEC 2016 – 9 –
INDUSTRIAL-PROCESS MEASUREMENT AND CONTROL –
DATA STRUCTURES AND ELEMENTS IN PROCESS
EQUIPMENT CATALOGUES –
Part 11: Lists of properties (LOPs) of measuring equipment
for electronic data exchange – Generic structures

1 Scope
This part of IEC 61987 provides:
• a characterisation of industrial process measuring equipment (device type dictionary) for
integration in the Common Data Dictionary (CDD), and
• generic structures for operating lists of properties (OLOP) and device lists of properties
(DLOP) of measuring equipment in conformance with IEC 61987-10.
The generic structures for the OLOP and DLOP contain the most important blocks for process
measuring equipment. Blocks pertaining to a specific equipment type will be described in the
corresponding part of the IEC 61987 standard series. Similarly, equipment properties are not
part of IEC 61987-11. For instance, the OLOP and DLOP for flow transmitters with blocks and
properties are to be found in IEC 61987-12.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements 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 60947-5-6, Low-voltage switchgear and controlgear – Part 5-6: Control circuit devices
and switching elements – DC interface for proximity sensors and switching amplifiers
(NAMUR)
IEC 61069-5, Industrial-process measurement, control and automation – Evaluation of system
properties for the purpose of system assessment – Part 5: Assessment of system
dependability
IEC 61508-6, Functional safety of electrical/electronic/programmable electronic safety-related
systems – Part 6: Guidelines on the application of IEC 61508-2 and IEC 61508-3
IEC 61987-1:2006, Industrial-process measurement and control – Data structures and
elements in process equipment catalogues – Part 1: Measuring equipment with analogue and
digital output
IEC 61987-10:2009, Industrial-process measurement and control – Data structures and
elements in process equipment catalogues – Part 10: Lists of Properties (LOPs) for Industrial-
Process Measurement and Control for Electronic Data Exchange – Fundamentals

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IEC 61987-92, Industrial-process measurement and control – Data structures and elements in
process equipment catalogues – Part 92: Lists of properties (LOPs) of measuring equipment
for electronic data exchange – aspect LOPs
IEC 62424, Representation of process control engineering – Requests in P&I diagrams and
data exchange between P&ID tools and PCE-CAE tools
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1 Terms and definitions concerning measuring instruments
3.1.1
composite device with main component
device composed of various devices, whereby one is designated the main component
EXAMPLE A control valve which consists of the valve itself (main component), an actuator and a positioner.
Note 1 to entry: These devices might be supplied as a whole or the parts comprising the assembly of the
composite device might be supplied individually.
3.1.2
gauge
measuring instrument intended to measure and indicate directly a measured value without
auxiliary energy supply
Note 1 to entry: In process engineering a gauge is often called an indicator.
Note 2 to entry: A gauge equipped with electrical contacts in order to transmit one or more measured values to
external equipment is still considered to be a gauge within the scope of this document.
3.1.3
instrument component
entity within a measuring instrument that plays a specific role and which can be handled
separately if necessary
EXAMPLE Thermowell within a temperature assembly, remote seal for a pressure transmitter.
3.1.4
integral transmitter
transmitter mounted as an integral part of an assembly containing the sensing element
3.1.5
measuring assembly
measuring instrument comprising several required and/or optional components which together
function as a gauge, transmitter or switch
Note 1 to entry: The components can often be ordered separately and as such require their own DLOPs.
Note 2 to entry: A measuring assembly may also be called a composite device.
_____________
To be published.
IEC 61987-11:2016 © IEC 2016 – 11 –
3.1.6
measuring instrument
automation equipment that detects an aspect of a material in order to record, transform or
display such an aspect or to perform a combination of these activities
3.1.7
PCE identifier/tag name
identifier assigned by the user to uniquely define the instrument or a component thereof
Note 1 to entry: PCE : Process Control Engineering.
3.1.8
sensing element
instrument component that is the primary element of a measuring chain and which may
convert the input variable into a signal suitable for use by other instruments in that chain
Note 1 to entry: It is intended to respond to a physical stimulus and to produce a corresponding resulting signal.
3.1.9
separate transmitter
transmitter mounted at a location removed (locally or remotely) from an assembly containing
the sensing element but connected to it by signal line
Note 1 to entry: A head-mounted transmitter is a separate transmitter mounted in a connection head.
3.1.10
sight indicator
measuring instrument that provides a means of visually inspecting a process regime and
provides only a qualitative indication
Note 1 to entry: IEC 60770-1 defines “indicator” as an instrument intended to visually indicate a physical quantity.
3.1.11
switch
measuring instrument that provides a discrete output signal representative of a process
regime
3.1.12
transmitter
instrument intended to transmit a standardized signal that represents the measured variable,
which may or may not include an integral sensing element
Note 1 to entry: A transmitter may also be equipped with the means to indicate a measured value.
Note 2 to entry: In process engineering a transmitter is often called a meter, for example flowmeter.
Note 3 to entry: A transmitter may also be a component of a composite device or measuring assembly.
3.2 Terms and definitions concerning relationships
3.2.1
aspect
specified way of viewing an object
EXAMPLE Such a way may be
– information about how to describe an object (device) – the describing aspect,
– information about the surrounding conditions in which a device operates – the operating aspect.
[SOURCE: IEC 81346-1:2009, 3.3]

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3.2.2
classification
non-transitive relationship indicating that the classified item is a member of the classifier class
EXAMPLE 1 The relationship that indicates that ‘London’ is a member of the class known as 'capital city' is known
as “classification”.
EXAMPLE 2 'pump' is_classified_as 'equipment type'.
Note 1 to entry: A subtype of relationship is transitive if when A is related to B, and B is related to C in the same
way, then A is necessarily related to C in that way. “specialization” and “composition” are examples of transitive
subtypes of relationship. However, because classification is not transitive does not mean that A cannot be related
to C in the same way, only that it does not necessarily follow from A being related to B and B being related to C.
Note 2 to entry: In this document the classification relationship is denoted as: is_classified_as.
[SOURCE: ISO 15926-2:2003, 5.2.2.3, modified – definition written according to IEC
guidelines; ‘thing’ replaced by ‘item’ for consistency reasons]
3.2.3
has_part
time-dependent transitive, reflexive, anti-symmetric relation identifying that an item has
another item as its part
EXAMPLE centrifugal pump has_part impeller during mounting.
Note 1 to entry: has_part is the inverse relation to is_part_of.
3.2.4
is_aspect_of
time-independent, anti-symmetric relation identifying that the LOP model of an aspect of a
device and the LOP model of the device are in relationship to each other, reflecting the
relationship between the device and its aspects
EXAMPLE The OLOP of a gauge is_aspect_of the DLOP of the gauge.
Note 1 to entry: IEC 61987-10 defines aspect as a specific way of selecting information on or describing a system
or an object of a system.
3.2.5
is_part_of
time-dependent transitive, reflexive, anti-symmetric relation identifying that an item is part of
another item
EXAMPLE impeller is_part_of centrifugal pump during mounting.
Note 1 to entry: C is_part_of C' if and only if: given any c that instantiates C at a time t, there is some c' such that
c' instantiates C' at time t, and c is_part_of c' at t.
Note 2 to entry: is_part_of is time-dependent. An item may be part of another item but will be disconnected later
during repair. In contrast the specialization and classification relation are time independent.
Note 3 to entry: The is_part_of relation may be used on level of devices and on level of individual components.
However, only the device level is in the scope of this document, since the standard does not deal with individuals.
3.2.6
specialization
transitive, anti-symmetric relation indicating that all knowledge provided for the generic item is
mandatory valid for the specialized item
EXAMPLE ‘Centrifugal pump’ is_a ‘pump’. All knowledge provided for ‘pump’ is mandatory valid for ‘centrifugal
pump’. If an individual is denoted as ‘centrifugal pump’, it is consequently also a ‘pump’ and all properties and
other information provided for ‘pump’ apply.
Note 1 to entry: If A is a specialization of B and B is a specialization of C, then A is necessarily a specialization of
C.
IEC 61987-11:2016 © IEC 2016 – 13 –
Note 2 to entry: In IEC 61987-11, the classification relationship i
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