ISO/FDIS 23247-6

Automation systems and integration — Digital twin framework for manufacturing — Part 6: Digital twin composition

This part of ISO 23247 specifies digital twin composition in manufacturing by defining principles, showing methodologies, and providing use case examples of configuration, communication, combination and collaboration between digital twins during manufacturing.

Systèmes d'automatisation et intégration — Cadre technique de jumeau numérique dans un contexte de fabrication — Partie 6: Composition d'un jumeau numérique

General Information

• Status: Not Published
• ICS: 25.040.40 - Industrial process measurement and control
• ICS: 35.240.50 - IT applications in industry
• Technical Committee: ISO/TC 184/SC 4 - Industrial data
• Drafting Committee: ISO/TC 184/SC 4 - Industrial data
• Current Stage: 5000 - FDIS registered for formal approval
• Start Date: 20-Feb-2026
• Completion Date: 25-Feb-2026

Overview

ISO/FDIS 23247-6 is part of the ISO 23247 series addressing automation systems and integration for manufacturing. This standard, specifically focused on the digital twin composition framework, provides internationally recognized guidance on configuring, combining, and collaborating with digital twins in manufacturing settings. ISO/FDIS 23247-6 defines the core principles for digital twin composition, methodologies for structuring and integrating digital twins, and illustrative use cases that facilitate practical implementation.

With the rising adoption of digital twins in manufacturing, the need for systematic approaches towards their composition is vital. This part of the standard enables organizations to efficiently leverage multiple, diverse digital twins from various sources, fostering improved interoperability, scalability, and reusability across complex manufacturing environments.

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Key Topics

Digital Twin Composition (DTC):

• The process of selecting, connecting, and combining digital twins to create a composed digital twin supporting more complex manufacturing tasks.
• DTC leverages existing digital twins as components, minimizing duplication of effort and promoting modular system design.

Types of Digital Twin Composition:

• Integrated DTC: Combines digital twins using a common schema and centralized control, ideal for systems requiring closely coordinated management, such as robotics.
• Unified DTC: Connects digital twins while preserving their individual models, relying on an interoperability layer or middleware to facilitate communication. Suited for integration across different vendors and standards.
• Federated DTC: Enables decentralized, peer-to-peer communication between digital twins. This approach supports direct interaction without a central authority, promoting flexibility in dynamic manufacturing environments.

Lifecycle Stages: A composed digital twin typically undergoes four stages:

• Specification: Define objectives and select the type of DTC.
• Design: Establish architecture, data standards, and communication protocols.
• Development: Configure data exchanges, interfaces, and test the integration.
• Operation: Deploy, monitor, and maintain the composed digital twin in live manufacturing processes.

Requirements:

• Consistent use of metadata, catalogues, and data standards
• Structured data exchange policies and access controls
• Adoption of standard APIs and interoperability layers
• Scalable and modular system architectures
• Comprehensive documentation and ongoing maintenance

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Applications

ISO/FDIS 23247-6 supports a wide variety of applications within smart manufacturing ecosystems, including:

• Real-time system monitoring: Combining digital twins of machines, tools, and processes to gain holistic, real-time insight into manufacturing operations.
• Predictive maintenance: Enabling the integration of machinery and component data for early fault detection and maintenance scheduling.
• Process optimization: Supporting advanced analytics and simulation by connecting data from various production lines, equipment, and products.
• Supply chain integration: Facilitating interoperability between digital twins developed by different suppliers and vendors, ensuring efficient and secure data flow.
• Automation and robotics: Composing digital twins for robotic arms, AGVs, and end effectors to create coordinated, adaptable automation solutions.

By applying the methodologies outlined in ISO/FDIS 23247-6, manufacturers can more easily achieve scalable digital transformation, reduce costs, and accelerate the path to fully integrated Industry 4.0 operations.

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Related Standards

• ISO 23247-1: General principles and requirements for digital twins in manufacturing
• ISO 23247-2: Reference architecture and functional views for manufacturing digital twins
• ISO 23247-3: Information attributes for observable manufacturing elements
• ISO 23247-4: Requirements for information exchange within the digital twin framework
• ISO 23247-5: Guidance on using digital threads in manufacturing lifecycle data management

These related standards provide the foundational guidance, architecture, and technical requirements that underpin the practical implementation of digital twin composition as described in ISO/FDIS 23247-6.

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Keywords: ISO 23247-6, digital twin composition, manufacturing digital twins, interoperability, automation systems, integration, Industry 4.0, smart factories, manufacturing standards, digital transformation.

Standards Content (Sample)

FINAL DRAFT
International
Standard
ISO/TC 184/SC 4
Automation systems and
Secretariat: ANSI
integration — Digital twin
Voting begins on:
framework for manufacturing —
2026-04-15
Part 6:
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2026-06-10
Digital twin composition
Systèmes d'automatisation et intégration — Cadre technique de
jumeau numérique dans un contexte de fabrication —
Partie 6: Composition d'un jumeau numérique
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Reference number
FINAL DRAFT
International
Standard
ISO/TC 184/SC 4
Automation systems and
Secretariat: ANSI
integration — Digital twin
Voting begins on:
framework for manufacturing —
2026-04-15
Part 6:
Voting terminates on:
2026-06-10
Digital twin composition
Systèmes d'automatisation et intégration — Cadre technique de
jumeau numérique dans un contexte de fabrication —
Partie 6: Composition d'un jumeau numérique
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
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Published in Switzerland Reference number
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, and abbreviated terms . 1
3.1 Terms and definitions .1
3.2 Abbreviated terms .3
4 Overview and benefits of digital twin composition . 3
4.1 Concept of digital twin composition .3
4.2 Benefits of digital twin composition .5
5 Classification of digital twin composition . 5
5.1 General .5
5.2 Integrated digital twin composition .6
5.3 Unified digital twin composition .6
5.4 Federated digital twin composition .7
5.5 Summary of digital twin composition kinds .8
6 Lifecycle of a digital twin composition . 9
6.1 General .9
6.2 Specification stage of a digital twin composition .10
6.3 Design stage of a digital twin composition .10
6.4 Development stage of a digital twin composition .11
6.5 Operation stage of a digital twin composition .11
7 Requirements of digital twin compositions .11
8 Development procedure for digital twin composition .13
8.1 Overview . 13
8.2 Deployment procedure for integrated digital twin composition . 13
8.3 Deployment procedure for unified digital twin composition.16
8.4 Deployment procedure for federated digital twin composition .18
Annex A (informative) Integrated digital twin composition use case — Robot arm with end
effector .20
Annex B (informative) Unified digital twin composition use case — Cutting process .24
Annex C (informative) Federated digital twin composition use case — Using an AGV to deliver
parts between automated assembly lines .27
Bibliography .31

iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
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with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
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For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 184, Automation systems and integration,
Subcommittee SC 4, Industrial data.
A list of all parts in the ISO 23247 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
Introduction
The ISO 23247 series defines a framework to support digital twins in manufacturing. A digital twin assists
with detecting events in manufacturing processes to achieve functional objectives such as real-time control,
predictive maintenance, in-process adaptation, big data analytics, process and manufactured component
validation, and machine learning. A digital twin monitors its observable manufacturing elements by
constantly updating and analysing relevant operational and environmental data as process/part changes.
This visibility into process and execution enabled by a digital twin enhances manufacturing operations and
business cooperation.
Manufacturing supported by implementing the ISO 23247 framework depends on the standards and
technologies available to model the observable manufacturing elements. Different manufacturing domains
can use different data standards. As a framework, this document does not prescribe specific data formats or
communication protocols.
The subject areas of the six parts of this series are defined below:
— ISO 23247-1: General principles and requirements for developing digital twins in manufacturing;
— ISO 23247-2: Reference architecture with functional views;
— ISO 23247-3: List of basic information attributes for the observable manufacturing elements;
— ISO 23247-4: Technical requirements for information exchange between entities within the reference
architecture;
— ISO 23247-5: Requirements and guidance to use digital threads for connecting manufacturing lifecycle
data to digital twins;
— ISO 23247-6: Requirements and guidance for performing digital twin composition.
Figure 1 shows how the six parts of the series are related.
Figure 1 — ISO 23247 series structure
Digital manufacturing involves many complex systems. One approach to managing manufacturing is to
create a digital twin encompassing all related assets. However, in practice, it is often impossible to build a
single digital twin that meets all the requirements for a factory floor or a supply chain. The digital twins of
each element in a complex system will need to be built independently and then integrated together using a

v
digital twin composition. With digital twin composition, individual digital twins can collaborate to enable
reusability and scalability, enabling individual digital twins to be used multiple times for various purposes,
rather than creating them from scratch every time.

vi
FINAL DRAFT International Standard ISO/FDIS 23247-6:2026(en)
Automation systems and integration — Digital twin
framework for manufacturing —
Part 6:
Digital twin composition
1 Scope
This document specifies digital twin compositions in manufacturing by defining principles, describing
methodologies and providing use-case examples of digital twin communication, aggregation and
interoperation.
This document identifies three kinds of digital twin composition (integrated, unified, and federated) and
specifies requirements and step-by-step implementation guidelines for each kind. It provides structured
approaches for composing multiple digital twins to support interoperability among digital twins developed
by different parties, such as vendors, solution providers, and in-house developers. The document also includes
illustrative use cases to demonstrate the practical application of the specified composition approaches.
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.
ISO 23247-1:2021, Automation systems and integration — Digital twin framework for manufacturing — Part 1:
Overview and general principles
ISO 23247-2:2021, Automation systems and integration — Digital twin framework for manufacturing — Part 2:
Reference architecture
3 Terms, definitions, and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in the ISO 23247-1, and the following
apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1.1
digital twin composition
DTC
process of selecting, connecting and combining digital twins
Note 1 to entry: Digital twin composition produces a composed digital twin (3.1.6) using component digital twins (3.1.5)

3.1.2
integrated digital twin composition
integration of component digital twins (3.1.5) using a common schema
3.1.3
unified digital twin composition
unification of component digital twins (3.1.5) while maintaining individual models and schemas
3.1.4
federated digital twin composition
federated communication between component digital twins (3.1.5) with peer-to-peer coordination
3.1.5
component digital twin
digital twin that participates in a digital twin composition (DTC) (3.1.1)
3.1.6
composed digital twin
digital twin produced by a digital twin composition (DTC) (3.1.1)
Note 1 to entry: The composed digital twin can be integrated, unified or federated.
Note 2 to entry: A composed digital twin can be a component digital twin for another DTC which can be a different
kind.
3.1.7
observable manufacturing element
OME
element that has an observable physical presence or operation in manufacturing
Note 1 to entry: Observable manufacturing elements include personnel, equipment, material, process, facility,
environment, product and supporting documentation.
[SOURCE: ISO 23247-1:2021, 3.2.5, modified — “item” was replaced by “element”.]
3.1.8
data exchange
exchange of machine-interpretable files
[SOURCE: ISO 10303-2:2024, 3.1.212, modified — Note 1 to entry deleted.]
3.1.9
data translation
conversion of a data value from one code set to another
[SOURCE: ISO/IEC 5207:2024, 3.12, modified — EXAMPLE 1, EXAMPLE 2 and Note 1 to entry deleted.]
3.1.10
data model
graphical, lexical or combined representation of data, specifying their properties, structure, and
interrelationships
[SOURCE: ISO/IEC 11179-1:2023, 3.2.24]

3.2 Abbreviated terms
P2P peer to peer
API application protocol interface
KPI key performance indicator
MQTT message queue telemetry transport
HTTP hypertext transfer protocol
OPC-UA open platform communications unified architecture
FE functional entity
TCP transmission control protocol
OMG object management group
IDL Interface definition language
ROS robot operating system
URDF unified robot description format
DDS data distribution service
PLM product lifecycle management
AGV automatic guided vehicle
4 Overview and benefits of digital twin composition
4.1 Concept of digital twin composition
Digital twin composition (DTC) refers to the process of selecting, connecting and combining digital twins to
achieve a new goal with complex tasks through cooperation, as shown in Figure 2.

Figure 2 — Concept of digital twin composition
In manufacturing, thousands of OMEs can be connected in various ways to achieve specific purposes and
capabilities. Different DTC approaches address different interoperability needs of digital twins, which also
reflect interoperability across physical elements. These DTC approaches can include combining physical
elements into a single piece of equipment, managing complex processes involving multiple OMEs, establishing
manufacturing hierarchies, and enabling dynamic communication through peer-to-peer networks.
To enhance the reusability and development efficiency of digital twins, a DTC leverages a digital twin
repository containing various types of digital twins, which can be selected and combined based on
specific manufacturing use-case needs. By utilising existing digital twins from shop floors or suppliers, a
DTC reduces the need to create new digital twins from scratch. The availability of composed digital twins
accelerates application development and minimizes redundant effort, enabling manufacturers to benefit
from existing resources and expertise.

4.2 Benefits of digital twin composition
DTC enables the efficient development of composed digital twins with the following benefits.
— Improving efficiency:
A composed digital twin enables efficient monitoring and analysis of system performance by identifying
how changes in individual components affect the overall system.
— Increasing flexibility:
A composed digital twin allows easy testing and evaluation of various scenarios and configurations by
modifying its components without significant changes to the entire system.
— Enhanced decision-making:
A composed digital twin facilitates the identification and analysis of interactions among different
system components.
— Reusability:
A composed digital twin enhances the reusability of component digital twins by minimizing constraints
related to modelling languages, application platforms and operating environments.
— Cost reduction:
A composed digital twin reduces the cost associated with designing, developing and operating digital
twins by leveraging existing digital twins rather than creating new ones from scratch.
— Rapid deployment:
A composed digital twin supports fast instantiation and interconnection of digital twins for
manufacturing systems, thereby reducing deployment time.
— Customisation:
A composed digital twin supports plug-and-play capabilities, enabling digital twin components to be
formulated through simplified interfacing and configuration.
— Scalability and extensibility:
A composed digital twin supports scalable and extensible designs using individual digital twins as
modular building blocks to represent complex manufacturing systems.
5 Classification of digital twin composition
5.1 General
The DTC is classified into three kinds based on the interoperability approaches defined in ISO 11354-1:
a) integrated DTC: a kind of DTC that supports the integrated interoperability approach;
b) unified DTC: a kind of DTC that supports the unified interoperability approach;
c) federated DTC: a kind of DTC that supports the federated interoperability approach.
Figure 3 illustrates the three kinds of DTCs.

Key
fixed connection with a common data format
data exchanges with translation
dynamic connection over a P2P network
Figure 3 — Three kinds of digital twin compositions
5.2 Integrated digital twin composition
An integrated DTC consolidates all data and functionalities from its component digital twins. The
component digital twins shall conform to a common data model and meet standardized protocols. This kind
of composed digital twin employs a centralized control to manage data and processes, ensuring consistency
and uniformity. However, the implementation process for integrated DTC can become complex and less
flexible as the number of component digital twins increases.
This kind of DTC is suitable for scenarios requiring centralised control, such as a robot digital twin composed
of a robot arm digital twin and an end-effector digital twin.
The characteristics of an integrated DTC are listed below.
— Interoperability design:
Data and processes are combined and controlled in a centralized manner.
— Representation format:
Uniform representation using common data models and standardised protocols.
— Identification:
Local identifiers are assigned to component digital twins within the composed digital twin.
— Dependency:
Component digital twins are tightly coupled by using the same data model and control logic, aligned
with the same system to ensure consistency throughout the operation.
— Data exchanges:
Fully supported through a common data model and information system, enabling standardized and
consistent data flow across the component digital twins.
— Digital thread connection:
Digital threads of the component digital twin are merged into the composed digital twin.
5.3 Unified digital twin composition
A unified DTC makes connections between multiple component digital twins while allowing each to maintain
its individual model and schema. Middleware, application programming interfaces (APIs), or data integration
platforms facilitate data exchange and interoperability between component digital twins. Interoperability is
achieved through centralised coordination called an interoperability layer, that supports data mapping and
translation, enabling diverse digital twins to communicate without forcing a single standard data model.

This kind of DTC is ideal for cases where digital twins are developed independently but require data
sharing. For example, a process digital twin is composed of a product digital twin, a machine digital twin,
tooling digital twins and a material digital twin that are developed by various vendors and using different
standards.
NOTE In this example, ISO 10303-238 can be used for data exchange between the various vendors in the
interoperability layer.
Characteristics of a unified DTC are listed below.
— Interoperability design:
An interoperability layer supports centralised coordination for data mapping, translation and facilitates
communication between component digital twins.
— Representation format:
A composed digital twin is represented as independent component digital twins and an interoperability
layer that coordinates data exchanges component digital twins.
— Identification:
Shared identification services or protocols across component digital twins shall be used. Identifiers
should be unique at least across the shared services or protocols.
— Dependency:
Component digital twins are loosely coupled with centralised coordination enabled through shared
interfaces and common data models.
— Data exchanges:
Efficient and compatible data exchange is supported through an interoperability layer that handles data
translation and mapping between shared models.
— Digital thread connection:
Digital threads of component digital twins are connected via an interoperability layer while each digital
thread is independently maintained.
5.4 Federated digital twin composition
In a federated DTC, component digital twins interact directly with each other without the need for a
coordinating entity that manages data exchange in a centralised manner. Each component digital twin can
request or provide services and data to or from other digital twins in the network. Due to the absence of
central control, decentralised coordination is achieved among component digital twins, which operates
independently while communicating directly with others, enabling dynamic and flexible interactions.
In this kind of DTC, adding a new digital twin in composed digital twin can be easy if the new component
digital twin was anticipated or difficult if the existing component digital twins need modification.
This kind of DTC is well suited to decentralized environments where autonomy and direct interaction are
essential, such as automatic guided vehicles coordinating tasks across multiple worksites.
Characteristics of federated DTCs are listed below.
— Interoperability design:
Interoperability is achieved by decentralised coordination through flexible interfaces and mutual
adjustments between component digital twins.

— Representation format:
Component digital twins retain their independent formats, and a composed digital twin is represented
as a set of connections between these digital twins with distributed control logic across the network.
— Identification:
A unique identifier is assigned to each component digital twin, enabling discovery and connection with
specified peers.
— Dependency:
Each component digital twin controls its corresponding OME using its own data, models and control
logic for a specific system or application.
— Data exchanges:
Data is exchanged peer-to-peer based on agreements through standard interfaces.
NOTE These agreements include contracts information such as service interface, data schemas for inputs and
outputs, expected quality of service, and security policies.
— Digital thread connection:
Each component digital twin connects its own independent digital thread and updates data in response
to changes by the federated digital twin.
5.5 Summary of digital twin composition kinds
Table 1 summarises aspects for each kind of DTC.
Table 1 — Summary of digital twin composition kinds
Aspects Integrated DTC Unified DTC Federated DTC
Description Integration of component Unification of component Federated communication
digital twins using a common digital twins while maintain- between component digital
schema. ing individual models and twins that meet service re-
schemas. quirements.
Compatibility with Limited Moderate High
other digital twins
Integration is based on com- Allows component digital New component digital twins
mon data models. If a com- twins with different data can freely join the network
ponent digital twin does not models, but the composed without significant changes to
share a common data model, digital twin must be reconfig- the existing systems.
then an integrated DTC is very ured.
difficult to accomplish.
Reliability High Moderate Low
This is due to the centralized The interoperability layer Depends on peer-to-peer
control and common proto- manages interactions and interactions and network
cols. failures across digital twins in capabilities.
a centralized manner.
Visualization Provides a consolidated view Requires visualising the Difficult to provide a holistic
of the system since all compo- component digital twins and view as each component op-
nents are tightly integrated their interactions through the erates independently with no
into a single digital twin. interoperability layer. centralized control.
State monitoring A centralized system allows Monitoring relies on the Requires monitoring of in-
easy monitoring of all compo- implementation quality of dependent digital twins and
nents and their interactions. the interoperability layer and aggregating data dynamically
middleware to collect and dis- from peer-to-peer interac-
play the status of component tions.
digital twins.
TTaabbllee 11 ((ccoonnttiinnueuedd))
Aspects Integrated DTC Unified DTC Federated DTC
Security Centralized control ensures The interoperability layer Decentralized security pro-
robust protection within the ensures data protection and tocols focus on peer-to-peer
composed system. access control across the con- encryption and access control
nected digital twins. to protect data integrity.
Complexity High; Low; High;
Centralised control system Central management is less Ensuring consistent peer-to-
required. complex. peer communications requires
complex solutions
Challenges Ensuring new components can Ensuring seamless connectiv- Ensuring robust peer-to-peer
be integrated into the com- ity through the interoperabil- communication for new com-
posed digital twin. ity layer. ponents.
Examples Robot integrated with its end Automated process unified Production line federated
effector for process monitor- with a cutter to optimize per- with multiple AGVs for sched-
ing. formance. ule optimization and resource
allocation.
NOTE Annex A describes a DTC using the integration method. Annex B describes a DTC using the unified method.
Annex C describes a DTC using the federation method.
Composed digital twin implementations can use any combination of the three, including multi-level and
hierarchical structures. In such cases, a single kind of DTC can be applied consistently across all levels, or
different DTC kinds can be mixed, depending on the purpose, structure and interoperability characteristics
of each component digital twin.
6 Lifecycle of a digital twin composition
6.1 General
The lifecycle of a DTC is divided into four stages in this document as following:
— Stage 1, specification;
— Stage 2, design;
— Stage 3, development; and
— Stage 4, operation.
The four stages are shown in Figure 4. These stages do not cover the entire lifecycle. For example, additional
stages can address decommissioning and the reuse of digital twins.

Key
operation flow
information flow
connection between digital twins
interface between entities
Figure 4 — Lifecycle stages of a digital twin composition
6.2 Specification stage of a digital twin composition
This stage defines the purpose and objectives of DTC. The appropriate kind of DTC can be selected based on
specific requirements and constraints. This stage consists of the following sub-steps.
— Define purposes and objectives to be achieved through the DTC.
— Establish requirements based on the defined purposes and objectives. These include:
— functional requirements such as target functionalities, data types, interfaces;
— non-functional requirements such as performance criteria, key performance indicators (KPIs),
energy efficiency or physical location of the composed and component digital twins.
NOTE The physical location (e.g. on-site, edge computing or in the cloud) of a composed digital twin is not the only
factor in determining the kind of DTC. Modern communication technology can transfer large quantities of data very
rapidly. Other factors such as security and firewalls can be as important.
— Select the appropriate kind of DTC (integrated, unified or federated) to fulfil the requirements and meet
the objectives.
— Create metadata for the composed digital twin that specifies its purpose and associated requirements.
— Examine the catalogue of the existing digital twins, including their functionalities, data formats,
technologies and interfaces.
6.3 Design stage of a digital twin composition
This stage defines the composition strategy for digital twins, based on the requirements, and the selected
DTC kind identified in the previous stage. It consists of the following sub-steps.
— Define DTC methods based on the composed digital twin metadata, which describe the functional
requirements and selected the DTC kind. These include:
— a system architecture to support composed digital twin(s);
— common data standards and formats; and

— communication protocols for data exchange between digital twins.
— Establish a plan for deploying the composed digital twin. The plan should define implementation
sequences for deploying the composed digital twin, and include a testing and evaluation plan for each
deployment step.
6.4 Development stage of a digital twin composition
This stage identifies and selects appropriate component digital twins that align with the established
composed digital twin design. It consists of the following sub-steps.
— Establish data exchanges and data mappings.
— Create interfaces needed.
— Deploy component digital twins that will be joined to the composed digital twin.
— Deploy middleware and APIs to interconnect component digital twins.
— Conduct testing, verification, and validation.
— Complete documentation of the DTC.
— Store the composed digital twin in a repository and catalogue of digital twins.
6.5 Operation stage of a digital twin composition
This stage deploys and executes the composed digital twin in parallel with the corresponding manufacturing
operation. It includes the following sub-steps.
— Connect or combine the component digital twins with shared data models, simulation algorithms and
user interfaces based on the previously defined plan.
— Configure data streams between component digital twins and synchronize between corresponding
OMEs.
— Update the composed digital twin continuously during operation.
— Establish a monitoring and maintenance process.
7 Requirements of digital twin compositions
Composition of multiple digital twins has several requirements to ensure seamless integration, consistency
and functionality. Table 2 provides a checklist of requirements for the DTC kinds. In the table, each
requirement shall be mapped to relevant DTC lifecycle stages and the applicable functional entities of the
digital twin framework as defined in ISO 23247-2.
Table 2 — Requirements of digital twin composition
Requirements
Integrated Unified Federated
Related stage
DTC DTC DTC
Mapping to FEs defined in ISO 23247-2
Metadata shall be used to describe DTC requirements,
such as the DTC kinds and functionalities of the composed
  
Specification
digital twin.
Digital representation FE, user interface FE
A catalogue shall be deployed in the system to include
functionalities, data models, technologies and interfaces of
Design   
existing digital twins.
Interoperability support FE, plug and play support FE

TTaabbllee 22 ((ccoonnttiinnueuedd))
Requirements
Integrated Unified Federated
Related stage
DTC DTC DTC
Mapping to FEs defined in ISO 23247-2
A common data model shall be adhered to by all compo-
nent digital twins, ensuring consistency in data formats,
Design 
structures and semantics.
Presentation FE, digital representation FE
Data sharing policies shall be defined for data sharing
and access control to manage how data is shared between
  
Design
component digital twins.
Access control FE, data assurance FE
Standard communication protocols and APIs shall be im-
plemented to facilitate communication between compo-
Design, develop-
  
nent digital twins.
ment
Peer interface FE
A scalable architecture should be designed and developed
to allow for the composition of additional digital twins
Design, develop-
 
without significant reconfiguration.
ment
Plug and Play support FE
An interoperability layer solution such as middleware
shall be used to implement an interoperability layer that
Design, develop-
facilitates data integration and communication between

ment
different digital twins.
Interoperability support FE, data translation FE
A decentralized network topology shall be designed and
developed to allow digital twins to communicate directly
Design, develop-

with each other without a central coordinating entity.
ment
Peer interface FE
Standard communication frameworks or protocols for
Design, develop-
peer-to-peer messaging shall be used.

ment
Peer interface FE
Mechanisms for data mapping and transformation shall be
identified or developed to translate data from component
  
Development
digital twins into a common format.
Data translation FE
Data synchronization mechanisms shall be implemented
to ensure timely data updates in all component digital
Development   
twins.
Synchronization FE
Peer discovery mechanisms shall be implemented so that
the component digital twins can dynamically discover
Development 
each other.
Peer interface FE, plug and play support FE
A graphical user interface shall be developed to provide a
comprehensive system view.
Development   
User interface FE, digital representation FE
Testing and evaluation shall be used to ensure seamless
data exchanges and operation between the component
Development   
digital twins.
Maintenance FE, reporting FE
The composed digital twin shall be documented and
stored in a repository.
Development   
Presentation FE
TTaabbllee 22 ((ccoonnttiinnueuedd))
Requirements
Integrated Unified Federated
Related stage
DTC DTC DTC
Mapping to FEs defined in ISO 23247-2
The component digital twins should be updated or re-
placed with minimum impact on the composed digital
Operation   
twin.
Synchronization FE, plug and play support FE
Data governance policies shall be established to manage
data quality, ownership and lifecycle.
Operation   
Data assurance FE
Flexible interaction models should be used to allow com-
ponent digital twins to dynamically form and dissolve
Operation 
connections based on the needs and conditions.
Peer interface FE
Data encryption shall be used to protect data, ensuring
privacy and security.
Operation   
Security support FE
Processes for supporting data consistency and quality
across the component digital twins shall be implemented.
Operation   
Data assurance FE
Maintenance procedures shall be established to monitor
the performance of digital twin systems and regularly
update, improve and optimize the system addressing any
  
Operation
issues that arise.
Maintenance FE, analytic service FE
The network should be resilient to failures, ensuring that
the failure of one or more component digital twins does
Operation   
not disrupt the entire system.
Maintenance FE, Peer interface FE
8 Development procedure for digital twin composition
8.1 Overview
In this section, detailed deployment procedures for each kind of DTC are described based on defined
requirements. Deployment procedures are illustrated with swimlane diagram, which shows process flows
by separating development stages. In these diagrams, the blocks in each stage represent functional steps
associated with different interoperability aspects in the lifecycle process described in Figure 4.
These steps generally include:
— defining the representation of exchanged data such as common data models, standardised protocols, or
semantic mappings;
— design the architectural basis that enables interoperability such as integrated architecture,
interoperability layer, or peer-to-peer coordination design; and
— implementing and validating the configuration through data mapping, functional integration, and
communication testing.
8.2 Deployment procedure for integrated digital twin composition
The implementation of an integrated DTC is shown in Figure 5. The procedure begins by defining
requirements and cataloguing existing digital twins during the specification stage. The DTC design
stage focuses on the definition of a common data model, creation of integrated ontologies, and design of

an architecture for the integrated digital twin. The DTC deployment stage establishes data exchange
mechanisms between component digital twins and implements an integration method by creating data
mapping rules and integrating functional modules. As a result, the composed digital twin is deployed. In
the DTC operation stage, the composed digital twin is running with continuous updates and a structured
maintenance process to ensure reliability and performance. By following these steps, a composed digital
twin can be implemented to consolidate the strengths and capabilities of multiple digital twins into a single,
larger digital twin that provides comprehensive, consistent, and real-time insights and functionalities.
It is challenging that extending an integrated DTC requires development of new functionalities to support the
new digital twin component. These functionalities can include data integration logic, interface adaptation,
or reconfiguration of the central control system to accommodate the added component. Such development
efforts can be challenging when the new component has different data models, communication protocols, or
operational behaviours.
Depending on the specific purpose and requirements, certain steps may be omitted, such as integration of a
user interface when it is not required.

Key
control flow
information flow
Figure 5 — Deployment procedure for integrated digital twin composition
...

ISO/TC 184/SC 4
Secretariat: ANSI
Date: 2026-0204-07
Automation systems and integration — Digital twin framework for
manufacturing — —
Part 6:
Digital twin composition
SystèmesSystèmes d'automatisation et intégration intégration — Cadre technique de jumeau
numériquenumérique dans un contexte de fabrication — —
Partie 6: Composition d'un jumeau numériquenumérique
FDIS stage
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ISO #####-#:####(X/FDIS 23247-6:2026(en)
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,
or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO
at the address below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
EmailE-mail: [e-mail]
Website: www.iso.org
Published in Switzerland
© ISO #### 2026 – All rights reserved
ii
ISO/DISFDIS 23247-6:20252026(en)
Contents
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, and abbreviated terms . 1
3.1 Terms and definitions . 1
3.2 Abbreviated terms . 2
4 Overview and benefits of digital twin composition . 3
4.1 Concept of digital twin composition . 3
4.2 Benefits of digital twin composition. 5
5 Classification of digital twin composition . 6
5.1 General . 6
5.2 Integrated digital twin composition . 7
5.3 Unified digital twin composition . 8
5.4 Federated digital twin composition . 9
5.5 Summary of digital twin composition kinds . 9
6 Lifecycle of a digital twin composition . 11
6.1 General . 11
6.2 Specification stage of a digital twin composition . 12
6.3 Design stage of a digital twin composition . 12
6.4 Development stage of a digital twin composition . 13
6.5 Operation stage of a digital twin composition . 13
7 Requirements of digital twin compositions . 13
8 Development procedure for digital twin composition . 15
8.1 Overview . 15
8.2 Deployment procedure for integrated digital twin composition . 16
8.3 Deployment procedure for unified digital twin composition . 19
8.4 Deployment procedure for federated digital twin composition . 22
Annex A (informative) Integrated digital twin composition use case — Robot arm with end
effector . 25
Annex B (informative) Unified digital twin composition use case — Cutting process . 30
Annex C (informative) Federated digital twin composition use case — Using an AGV to deliver
parts between automated assembly lines . 34
Bibliography . 39

iii
ISO #####-#:####(X/FDIS 23247-6:2026(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of
ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Field Code Changed
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
Field Code Changed
This document was prepared by Technical Committee ISO/TC 184, Automation systems and integration,
Subcommittee SC 4, Industrial data.
A list of all parts in the ISO 23247 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
Field Code Changed
© ISO #### 2026 – All rights reserved
iv
ISO/DISFDIS 23247-6:20252026(en)
Introduction
The ISO 23247 series defines a framework to support digital twins in manufacturing. A digital twin assists
with detecting events in manufacturing processes to achieve functional objectives such as real-time control,
predictive maintenance, in-process adaptation, big data analytics, process and manufactured component
validation, and machine learning. A digital twin monitors its observable manufacturing elements by constantly
updating and analysing relevant operational and environmental data as process/part changes. This visibility
into process and execution enabled by a digital twin enhances manufacturing operations and business
cooperation.
Manufacturing supported by implementing the ISO 23247 framework depends on the standards and
technologies available to model the observable manufacturing elements. Different manufacturing domains can
use different data standards. As a framework, this document does not prescribe specific data formats or
communication protocols.
The subject areas of the six parts of this series are defined below:
— — ISO 23247-1: General principles and requirements for developing digital twins in manufacturing;
— — ISO 23247-2: Reference architecture with functional views;
— — ISO 23247-3: List of basic information attributes for the observable manufacturing elements;
— — ISO 23247-4: Technical requirements for information exchange between entities within the reference
architecture;
— — ISO 23247-5: Requirements and guidance to use digital threads for connecting manufacturing lifecycle
data to digital twins;
— — ISO 23247-6: Requirements and guidance for performing digital twin composition.
Figure 1Figure 1 shows how the six parts of the series are related.
v
ISO #####-#:####(X/FDIS 23247-6:2026(en)

Figure 1— ISO 23247 series structure
Digital manufacturing involves many complex systems. One approach to managing manufacturing is to create
a digital twin encompassing all related assets. However, in practice, it is often impossible to build a single
digital twin that meets all the requirements for a factory floor or a supply chain. The digital twins of each
element in a complex system will need to be built independently and then integrated together using a digital
twin composition. With digital twin composition, individual digital twins can collaborate to enable reusability
and scalability, enabling individual digital twins to be used multiple times for various purposes, rather than
creating them from scratch every time.
© ISO #### 2026 – All rights reserved
vi
DRAFT International Standard ISO/DIS 23247-6:2025(en)

Automation systems and integration — Digital twin framework for
manufacturing — —
Part 6:
Digital twin composition
1 Scope
This document specifies digital twin compositions in manufacturing by defining principles, describing
methodologies and providing use-case examples of digital twin communication, aggregation and
interoperation.
This document identifies three kinds of digital twin composition (integrated, unified, and federated) and
specifies requirements and step-by-step implementation guidelines for each kind. It provides structured
approaches for composing multiple digital twins to support interoperability among digital twins developed
by different parties, such as vendors, solution providers, and in-house developers. The document also includes
illustrative use cases to demonstrate the practical application of the specified composition approaches.
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.
ISO 23247-1:2021, Automation systems and integration — Digital twin framework for manufacturing — Part
1: Overview and general principles
ISO 23247-2:2021, Automation systems and integration — Digital twin framework for manufacturing — Part
2: Reference architecture
3 Terms, definitions, and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in the ISO 23247-1, and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— — ISO Online browsing platform: available at https://www.iso.org/obp
— — IEC Electropedia: available at https://www.electropedia.org/
3.1.1 3.1.1
digital twin composition
DTC
process of selecting, connecting and combining digital twins
Note 1 to entry: Digital twin composition produces a composed digital twin (3.1.6(3.1.6)) using component digital twins
(3.1.5(3.1.5))
3.1.2 3.1.2
integrated digital twin composition
integration of component digital twins (3.1.5(3.1.5)) using a common schema
3.1.3 3.1.3
unified digital twin composition
unification of component digital twins (3.1.5(3.1.5)) while maintaining individual models and schemas
3.1.4 3.1.4
federated digital twin composition
federated communication between component digital twins (3.1.5(3.1.5)) with peer-to-peer coordination
3.1.5 3.1.5
component digital twin
digital twin that participates in a digital twin composition (DTC) (3.1.1(3.1.1) )
3.1.6 3.1.6
composed digital twin
digital twin produced by a digital twin composition (DTC) (3.1.1(3.1.1))
Note 1 to entry: The composed digital twin can be integrated, unified or federated.
Note 2 to entry: A composed digital twin can be a component digital twin for another DTC which can be a different kind.
3.1.7 3.1.7
observable manufacturing element
OME
element that has an observable physical presence or operation in manufacturing
Note 1 to entry: Observable manufacturing elements include personnel, equipment, material, process, facility,
environment, product and supporting documentation.
[SOURCE: ISO 23247-1:2021, 3.2.5, modified — “item” was replaced by “element”.]
3.1.8 3.1.8
data exchange
exchange of machine-interpretable files
[SOURCE: ISO 10303-2:2024, 3.1.212, modified — Note 1 to entry deleted.]
3.1.9 3.1.9
data translation
conversion of a data value from one code set to another
[SOURCE: ISO/IEC 5207:2024, 3.12, modified — EXAMPLE 1, EXAMPLE 2 and Note 1 to entry deleted.]
3.1.10 3.1.10
data model
graphical, lexical or combined representation of data, specifying their properties, structure, and
interrelationships
[SOURCE: ISO/IEC 11179-1:2023, 3.2.24]
3.2 Abbreviated terms
P2P peer to peer
© ISO #### 2026 – All rights reserved
ISO/DISFDIS 23247-6:20252026(en)
API application protocol interface
KPI key performance indicator
MQTT message queue telemetry transport
HTTP hypertext transfer protocol
OPC-UA open platform communications unified architecture
FE functional entity
TCP transmission control protocol
OMG object management group
IDL Interface definition language
ROS robot operating system
URDF unified robot description format
DDS data distribution service
PLM product lifecycle management
AGV automatic guided vehicle
4 Overview and benefits of digital twin composition
4.1 Concept of digital twin composition
Digital twin composition (DTC) refers to the process of selecting, connecting and combining digital twins to
achieve a new goal with complex tasks through cooperation, as shown in Figure 2Figure 2.
© ISO #### 2026 – All rights reserved
ISO/DISFDIS 23247-6:20252026(en)

Figure 2— Concept of digital twin composition
In manufacturing, thousands of OMEs can be connected in various ways to achieve specific purposes and
capabilities. Different DTC approaches address different interoperability needs of digital twins, which also
reflect interoperability across physical elements. These DTC approaches can include combining physical
elements into a single piece of equipment, managing complex processes involving multiple OMEs, establishing
manufacturing hierarchies, and enabling dynamic communication through peer-to-peer networks.
To enhance the reusability and development efficiency of digital twins, a DTC leverages a digital twin
repository containing various types of digital twins, which can be selected and combined based on specific
manufacturing use-case needs. By utilising existing digital twins from shop floors or suppliers, a DTC reduces
the need to create new digital twins from scratch. The availability of composed digital twins accelerates
application development and minimizes redundant effort, enabling manufacturers to benefit from existing
resources and expertise.
4.2 Benefits of digital twin composition
DTC enables the efficient development of composed digital twins with the following benefits.
— — Improving efficiency:
A composed digital twin enables efficient monitoring and analysis of system performance by identifying
how changes in individual components affect the overall system.
— — Increasing flexibility:
A composed digital twin allows easy testing and evaluation of various scenarios and configurations by
modifying its components without significant changes to the entire system.
— — Enhanced decision-making:
A composed digital twin facilitates the identification and analysis of interactions among different system
components.
— — Reusability:
A composed digital twin enhances the reusability of component digital twins by minimizing constraints
related to modelling languages, application platforms and operating environments.
— — Cost reduction:
A composed digital twin reduces the cost associated with designing, developing and operating digital
twins by leveraging existing digital twins rather than creating new ones from scratch.
— — Rapid deployment:
A composed digital twin supports fast instantiation and interconnection of digital twins for manufacturing
systems, thereby reducing deployment time.
— — Customisation:
A composed digital twin supports plug-and-play capabilities, enabling digital twin components to be
formulated through simplified interfacing and configuration.
— — Scalability and extensibility:
A composed digital twin supports scalable and extensible designs using individual digital twins as
modular building blocks to represent complex manufacturing systems.
5 Classification of digital twin composition
5.1 General
The DTC is classified into three kinds based on the interoperability approaches defined in ISO 11354-1:
a) a) integrated DTC: a kind of DTC that supports the integrated interoperability approach;
b) b) unified DTC: a kind of DTC that supports the unified interoperability approach;
c) c) federated DTC: a kind of DTC that supports the federated interoperability approach.
Figure 3Figure 3 illustrates the three kinds of DTCs.
© ISO #### 2026 – All rights reserved
ISO/DISFDIS 23247-6:20252026(en)

Key
fixed connection with a common data format

data exchanges with translation

dynamic connection over a P2P network

Figure 3— Three kinds of digital twin compositions
5.2 Integrated digital twin composition
An integrated DTC consolidates all data and functionalities from its component digital twins. The component
digital twins shall conform to a common data model and meet standardized protocols. This kind of composed
digital twin employs a centralized control to manage data and processes, ensuring consistency and uniformity.
However, the implementation process for integrated DTC can become complex and less flexible as the number
of component digital twins increases.
This kind of DTC is suitable for scenarios requiring centralised control, such as a robot digital twin composed
of a robot arm digital twin and an end-effector digital twin.
The characteristics of an integrated DTC are listed below.
— — Interoperability design:
Data and processes are combined and controlled in a centralized manner.
— — Representation format:
Uniform representation using common data models and standardised protocols.
— — Identification:
Local identifiers are assigned to component digital twins within the composed digital twin.
— — Dependency:
Component digital twins are tightly coupled by using the same data model and control logic, aligned with
the same system to ensure consistency throughout the operation.
— — Data exchanges:
Fully supported through a common data model and information system, enabling standardized and
consistent data flow across the component digital twins.
— — Digital thread connection:
Digital threads of the component digital twin are merged into the composed digital twin.
5.3 Unified digital twin composition
A unified DTC makes connections between multiple component digital twins while allowing each to maintain
its individual model and schema. Middleware, application programming interfaces (APIs), or data integration
platforms facilitate data exchange and interoperability between component digital twins. Interoperability is
achieved through centralised coordination called an interoperability layer, that supports data mapping and
translation, enabling diverse digital twins to communicate without forcing a single standard data model.
This kind of DTC is ideal for cases where digital twins are developed independently but require data sharing.
For example, a process digital twin is composed of a product digital twin, a machine digital twin, tooling digital
twins and a material digital twin that are developed by various vendors and using different standards.
NOTE — In this example, ISO 10303-238 can be used for data exchange between the various vendors in the
interoperability layer.
Characteristics of a unified DTC are listed below.
— — Interoperability design:
An interoperability layer supports centralised coordination for data mapping, translation and facilitates
communication between component digital twins.
— — Representation format:
A composed digital twin is represented as independent component digital twins and an interoperability
layer that coordinates data exchanges component digital twins.
— — Identification:
Shared identification services or protocols across component digital twins shall be used. Identifiers
should be unique at least across the shared services or protocols.
— — Dependency:
Component digital twins are loosely coupled with centralised coordination enabled through shared
interfaces and common data models.
— — Data exchanges:
Efficient and compatible data exchange is supported through an interoperability layer that handles data
translation and mapping between shared models.
— — Digital thread connection:
© ISO #### 2026 – All rights reserved
ISO/DISFDIS 23247-6:20252026(en)
Digital threads of component digital twins are connected via an interoperability layer while each digital
thread is independently maintained.
5.4 Federated digital twin composition
In a federated DTC, component digital twins interact directly with each other without the need for a
coordinating entity that manages data exchange in a centralised manner. Each component digital twin can
request or provide services and data to or from other digital twins in the network. Due to the absence of central
control, decentralised coordination is achieved among component digital twins, which operates
independently while communicating directly with others, enabling dynamic and flexible interactions.
In this kind of DTC, adding a new digital twin in composed digital twin can be easy if the new component digital
twin was anticipated or difficult if the existing component digital twins need modification.
This kind of DTC is well suited to decentralized environments where autonomy and direct interaction are
essential, such as automatic guided vehicles coordinating tasks across multiple worksites.
Characteristics of federated DTCs are listed below.
— — Interoperability design:
Interoperability is achieved by decentralised coordination through flexible interfaces and mutual
adjustments between component digital twins.
— — Representation format:
Component digital twins retain their independent formats, and a composed digital twin is represented as
a set of connections between these digital twins with distributed control logic across the network.
— — Identification:
AnA unique identifier is assigned to each component digital twin, enabling discovery and connection with
specified peers.
— — Dependency:
Each component digital twin controls its corresponding OME using its own data, models and control logic
for a specific system or application.
— — Data exchanges:
Data is exchanged peer-to-peer based on agreements through standard interfaces.
NOTE — These agreements include contracts information such as service interface, data schemas for inputs and
outputs, expected quality of service, and security policies.
— — Digital thread connection:
Each component digital twin connects its own independent digital thread and updates data in response
to changes by the federated digital twin.
5.5 Summary of digital twin composition kinds
Table 1Table 1 summarises aspects for each kind of DTC.
Table 1— Summary of digital twin composition kinds
Aspects Integrated DTC Unified DTC Federated DTC
Description Integration of component Unification of component Federated communication
digital twins using a common digital twins while between component digital
schema. maintaining individual twins that meet service
models and schemas. requirements.
Compatibility with Limited Moderate High
other digital twins
Integration is based on Allows component digital New component digital twins
common data models. If a twins with different data can freely join the network
component digital twin does models, but the composed without significant changes
not share a common data digital twin must be to the existing systems.
model, then an integrated reconfigured.
DTC is very difficult to
accomplish.
Reliability High Moderate Low
This is due to the centralized The interoperability layer Depends on peer-to-peer
control and common manages interactions and interactions and network
protocols. failures across digital twins capabilities.
in a centralized manner.
Visualization Provides a consolidated view Requires visualising the Difficult to provide a holistic
of the system since all component digital twins and view as each component
components are tightly their interactions through the operates independently with
integrated into a single interoperability layer. no centralized control.
digital twin.
State monitoring A centralized system allows Monitoring relies on the Requires monitoring of
easy monitoring of all implementation quality of the independent digital twins
components and their interoperability layer and and aggregating data
interactions. middleware to collect and dynamically from peer-to-
display the status of peer interactions.
component digital twins.
Security Centralized control ensures The interoperability layer Decentralized security
robust protection within the ensures data protection and protocols focus on peer-to-
composed system. access control across the peer encryption and access
connected digital twins. control to protect data
integrity.
Complexity High; Low; High;
Centralised control system Central management is less Ensuring consistent peer-to-
required. complex. peer communications
requires complex solutions
Challenges Ensuring new components Ensuring seamless Ensuring robust peer-to-peer
can be integrated into the connectivity through the communication for new
composed digital twin. interoperability layer. components.
Examples Robot integrated with its end Automated process unified Production line federated
effector for process with a cutter to optimize with multiple AGVs for
monitoring. performance. schedule optimization and
resource allocation.
NOTE Annex A — Annex A describes a DTC using the integration method. Annex BAnnex B describes a DTC using
the unified method. Annex CAnnex C describes a DTCnDTC using the federation method.
Composed digital twin implementations can use any combination of the three, including multi-level and
hierarchical structures. In such cases, a single kind of DTC can be applied consistently across all levels, or
© ISO #### 2026 – All rights reserved
ISO/DISFDIS 23247-6:20252026(en)
different DTC kinds can be mixed, depending on the purpose, structure and interoperability characteristics of
each component digital twin.
6 Lifecycle of a digital twin composition
6.1 General
The lifecycle of a DTC is divided into four stages in this document as following:
— Stage 1, specification;
— Stage 2, design;
— Stage 3, development; and
— Stage 4, operation.
The four stages are shown in Figure 4Figure 4. These stages do not cover the entire lifecycle. For example,
additional stages can address decommissioning and the reuse of digital twins.

Key
operation flow
information flow
connection between digital twins

interface between entities
Figure 4— Lifecycle stages of a digital twin composition
6.2 Specification stage of a digital twin composition
This stage defines the purpose and objectives of DTC. The appropriate kind of DTC can be selected based on
specific requirements and constraints. This stage consists of the following sub-steps.
— — Define purposes and objectives to be achieved through the DTC.
— — Establish requirements based on the defined purposes and objectives. These include:
— — functional requirements such as target functionalities, data types, interfaces;
— — non-functional requirements such as performance criteria, key performance indicators (KPIs),
energy efficiency or physical location of the composed and component digital twins.
NOTE — The physical location (for examplee.g. on-site, edge computing or in the cloud) of a composed digital twin
is not the only factor in determining the kind of DTC. Modern communication technology can transfer large quantities of
data very rapidly. Other factors such as security and firewalls can be as important.
— — Select the appropriate kind of DTC (integrated, unified or federated) to fulfil the requirements and
meet the objectives.
— — Create metadata for the composed digital twin that specifies its purpose and associated requirements.
— — Examine the catalogue of the existing digital twins, including their functionalities, data formats,
technologies and interfaces.
6.3 Design stage of a digital twin composition
This stage defines the composition strategy for digital twins, based on the requirements, and the selected DTC
kind identified in the previous stage. It consists of the following sub-steps.
— — Define DTC methods based on the composed digital twin metadata, which describe the functional
requirements and selected the DTC kind. These include:
— — Aa system architecture to support composed digital twin(s);
— — Commoncommon data standards and formats; and
— — Communicationcommunication protocols for data exchange between digital twins.
— — Establish a plan for deploying the composed digital twin. The plan should define implementation
sequences for deploying the composed digital twin, and include a testing and evaluation plan for each
deployment step.
© ISO #### 2026 – All rights reserved
ISO/DISFDIS 23247-6:20252026(en)
6.4 Development stage of a digital twin composition
This stage identifies and selects appropriate component digital twins that align with the established composed
digital twin design. It consists of the following sub-steps.
— — Establish data exchanges and data mappings.
— — Create interfaces needed.
— — Deploy component digital twins that will be joined to the composed digital twin.
— — Deploy middleware and APIs to interconnect component digital twins.
— — Conduct testing, verification, and validation.
— — Complete documentation of the DTC.
— — Store the composed digital twin in a repository and catalogue of digital twins.
6.5 Operation stage of a digital twin composition
This stage deploys and executes the composed digital twin in parallel with the corresponding manufacturing
operation. It includes the following sub-steps.
— — Connect or combine the component digital twins with shared data models, simulation algorithms and
user interfaces based on the previously defined plan.
— — Configure data streams between component digital twins and synchronize between corresponding
OMEs.
— — Update the composed digital twin continuously during operation.
— — Establish a monitoring and maintenance process.
7 Requirements of digital twin compositions
Composition of multiple digital twins has several requirements to ensure seamless integration, consistency
and functionality. Table 2Table 2 provides a checklist of requirements for the DTC kinds. In the table, each
requirement isshall be mapped to relevant DTC lifecycle stages and the applicable functional entities of the
digital twin framework as defined in ISO 23247-2.
Table 2— Requirements of digital twin composition
Requirements
Related Integrat Unified Federate
stage ed DTC DTC d DTC
Mapping to FEs defined in ISO 23247-2
Metadata shall be used to describe DTC requirements,
such as the DTC kinds and functionalities of the composed
Specification ✓ ✓ ✓
digital twin.
Digital representation FE, user interface FE
A catalogue shall be deployed in the system to include
functionalities, data models, technologies and interfaces
Design ✓ ✓ ✓
of existing digital twins.
Interoperability support FE, plug and play support FE
Requirements
Related Integrat Unified Federate
stage ed DTC DTC d DTC
Mapping to FEs defined in ISO 23247-2
A common data model shall be adhered to by all
component digital twins, ensuring consistency in data
Design ✓
formats, structures and semantics.
Presentation FE, digital representation FE
Data sharing policies shall be defined for data sharing and
access control to manage how data is shared between
Design ✓ ✓ ✓
component digital twins.
Access control FE, data assurance FE
Standard communication protocols and APIs shall be
implemented to facilitate communication between
Design,
✓ ✓ ✓
component digital twins.
development
Peer interface FE
A scalable architecture should be designed and developed
to allow for the composition of additional digital twins
Design,
✓ ✓
without significant reconfiguration.
development
Plug and Play support FE
An interoperability layer solution such as middleware
shall be used to implement an interoperability layer that
Design,
facilitates data integration and communication between
✓
development
different digital twins.
Interoperability support FE, data translation FE
A decentralized network topology shall be designed and
developed to allow digital twins to communicate directly
Design,
✓
with each other without a central coordinating entity.
development
Peer interface FE
Standard communication frameworks or protocols for
Design,
peer-to-peer messaging shall be used.

✓
development
Peer interface FE
Mechanisms for data mapping and transformation shall
be identified or developed to translate data from
Development ✓ ✓ ✓
component digital twins into a common format.
Data translation FE
Data synchronization mechanisms shall be implemented
to ensure timely data updates in all component digital
Development ✓ ✓ ✓
twins.
Synchronization FE
Peer discovery mechanisms shall be implemented so that
the component digital twins can dynamically discover
Development   ✓
each other.
Peer interface FE, plug and play support FE
A graphical user interface shall be developed to provide a
comprehensive system view.
Development
✓ ✓ ✓
User interface FE, digital representation FE
© ISO #### 2026 – All rights reserved
ISO/DISFDIS 23247-6:20252026(en)
Requirements
Related Integrat Unified Federate
stage ed DTC DTC d DTC
Mapping to FEs defined in ISO 23247-2
Testing and evaluation shall be used to ensure seamless
data exchanges and operation between the component
Development
✓ ✓ ✓
digital twins.
Maintenance FE, reporting FE
The composed digital twin shall be documented and
stored in a repository.
Development ✓ ✓ ✓
Presentation FE
The component digital twins should be updated or
replaced with minimum impact on the composed digital
Operation
✓ ✓ ✓
twin.
Synchronization FE, plug and play support FE
Data governance policies shall be established to manage
data quality, ownership and lifecycle.
Operation ✓ ✓ ✓
Data assurance FE
Flexible interaction models should be used to allow
component digital twins to dynamically form and dissolve
Operation   ✓
connections based on the needs and conditions.
Peer interface FE
Data encryption shall be used to protect data, ensuring
privacy and security.
Operation
✓ ✓ ✓
Security support FE
Processes for supporting data consistency and quality
across the component digital twins shall be implemented.
Operation ✓ ✓ ✓
Data assurance FE
Maintenance procedures shall be established to monitor
the performance of digital twin systems and regularly
update, improve and optimize the system addressing any
Operation ✓ ✓ ✓
issues that arise.
Maintenance FE, analytic service FE
The network should be resilient to failures, ensuring that
the failure of one or more component digital twins does
Operation ✓ ✓ ✓
not disrupt the entire system.
Maintenance FE, Peer interface FE
8 Development procedure for digital twin composition
8.1 Overview
In this section, detailed deployment procedures for each kind of DTC are described based on defined
requirements. Deployment procedures are illustrated with swimlane diagram, which shows process flows by
separating development stages. In these diagrams, the blocks in each stage represent functional steps
associated with different interoperability aspects in the lifecycle process described in Figure 4Figure 4.
These steps generally include:
— defining the representation of exchanged data such as common data models, standardised protocols, or
semantic mappings;
— design the architectural basis that enables interoperability such as integrated architecture,
interoperability layer, or peer-to-peer coordination design; and
— implementing and validating the configuration through data mapping, functional integration, and
communication testing.
8.2 Deployment procedure for integrated digital twin composition
The implementation of an integrated DTC is shown in Figure 5Figure 5. The procedure begins by defining
requirements and cataloguing existing digital twins during the specification stage. The DTC design stage
focuses on the definition of a common data model, creation of integrated ontologies, and design of an
architecture for the integrated digital twin. The DTC deployment stage establishes data exchange mechanisms
between component digital twins and implements an integration method by creating data mapping rules and
integrating functional modules. As a result, the composed digital twin is deployed. In the DTC operation stage,
the composed digital twin is running with continuous updates and a structured maintenance process to ensure
reliability and performance. By following these steps, a composed digital twin can be implemented to
consolidate the strengths and capabilities of multiple digital twins into a single, larger digital twin that
provides comprehensive, consistent, and real-time insights and functionalities.
It is challenging that extending an integrated DTC requires development of new functionalities to support the
new digital twin component. These functionalities can include data integration logic, interface adaptation, or
reconfiguration of the central control system to accommodate the added component. Such development
efforts can be challenging when the new component has different data models, communication protocols, or
operational behaviours.
Depending on the specific purpose and requirements, certain steps may be omitted, such as integration of a
user interface when it is not required.
© ISO #### 2026 – All rights reserved
ISO/DISFDIS 23247-6:20252026(en)

Key
control flow
information flow
© ISO #### 2026 – All rights reserved
ISO/DISFDIS 23247-6:20252026(en)

Figure 5— Deployment procedure for integrated digital twin composition
8.3 Deployment procedure for unified digital twin composition
Implementation of unified DTC is shown in Figure 6Figure 6. Unifying multiple digital twins involves a
structured approach to ensure interoperability, consistency and efficient data exchange among different
digital twins. The process begins with defining requirements and cataloguing existing digital twins. In the
design stage, a system architecture of the interoperability layers with standard communication protocols is
defined. Also, since the interoperability layer is needed to coordinate between component digital twins,
integration plans in the DTC design stage are established. The DTC deployment stage focuses on developing
the interoperability layer, including middleware and data mapping schemas. By attaching component digital
twins to the interoperability layer and testing and evaluating the system, the composed digital twin can be
deployed with monitoring to
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