ISO 23247-4:2021

Automation systems and integration - Digital twin framework for manufacturing - Part 4: Information exchange

This document identifies technical requirements for information exchange between entities within the reference architecture. The requirements for information exchange in the following networks are within the scope of this document: - user network that connects the user entity and the digital twin entity; - service network that connects sub-entities within the digital twin entity; - access network that connects the device communication entity to the digital twin entity and to the user entity; - proximity network that connects the device communication entity to the observable manufacturing elements.

Systèmes d'automatisation industrielle et intégration — Cadre technique de jumeau numérique dans un contexte de fabrication — Partie 4: Échange d'informations

General Information

• Status: Published
• Publication Date: 11-Oct-2021
• 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/WG 15 - Digital manufacturing
• Current Stage: 6060 - International Standard published
• Start Date: 12-Oct-2021
• Due Date: 18-Jan-2021
• Completion Date: 12-Oct-2021

Overview

ISO 23247-4:2021 - "Automation systems and integration - Digital twin framework for manufacturing - Part 4: Information exchange" defines technical requirements for how information is exchanged among entities in a digital twin reference architecture for manufacturing. It focuses on four network types that connect users, services, device communication layers, and observable manufacturing elements (OMEs). The document complements ISO 23247-1 (principles), -2 (reference architecture) and -3 (information attributes) and does not prescribe specific data formats or communication protocols.

Key Topics and Technical Requirements

ISO 23247-4:2021 addresses the networking view and lays out concrete requirements for information exchange across the digital twin framework. Key topics include:

• Four network types:
  • User network: connects user entities (humans, applications, enterprise systems) with the digital twin entity.
  • Service network: links sub-entities inside the digital twin entity (operation/management, application/service, resource access).
  • Access network: connects device communication entities to digital twin and user entities (typically IP-based LAN/WLAN/mobile).
  • Proximity network: connects device communication entities to OMEs (may use Industrial Ethernet or non‑IP protocols).
• User network requirements: provisioning, on‑demand status acquisition, standardized exchange methods, verification of exchanged digital models, synchronization, security, and support for visualisation, monitoring and simulation.
• Service network requirements: reliable internal exchange among digital twin sub‑entities to support management, data analytics and simulation.
• Access network requirements: connectivity, standardized communication methods, synchronization, transaction handling, mobility support, and security considerations.
• Proximity network requirements: local connectivity support, adaptation for device specifics, and handling of data volume, transmission efficiency and storage constraints.
• Implementation guidance: informative annexes provide discrete manufacturing use cases (dynamic scheduling, advanced metrology, material removal optimization) illustrating practical exchanges between models and systems.

Applications and Who Uses It

ISO 23247-4 is for organizations implementing or integrating digital twin solutions in manufacturing. Typical users and beneficiaries:

• Manufacturing companies deploying digital twins for real‑time control, predictive maintenance, in‑process adaptation, and analytics
• OT/IT system architects and automation engineers defining network and data exchange requirements
• System integrators and software vendors building digital twin platforms, APIs and device communication stacks
• Standards developers and researchers aligning data exchange practices across manufacturing domains

Practical benefits include improved interoperability, robust synchronization between physical assets and their twin models, secured information flows, and clear requirements for supporting mobile or constrained devices.

Related Standards (if applicable)

• ISO 23247-1: Overview and general principles (digital twin framework)
• ISO 23247-2: Reference architecture and functional views
• ISO 23247-3: Basic information attributes for observable manufacturing elements
• Domain modeling examples referenced: ISO 10303 (discrete manufacturing), ISO 15926 (process/oil & gas), ISO 16739 (building information modeling)

Keywords: ISO 23247-4:2021, digital twin, information exchange, manufacturing, user network, service network, access network, proximity network, industrial interoperability.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 23247-4
First edition
2021-10
Automation systems and
integration — Digital twin framework
for manufacturing —
Part 4:
Information exchange
Systèmes d'automatisation industrielle et intégration — Cadre
technique de jumeau numérique dans un contexte de fabrication —
Partie 4: Échange d'informations
Reference number
© ISO 2021
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: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Networking view of the digital twin reference models . 2
4.1 Overview . 2
4.2 User network . 3
4.3 Service network . 3
4.4 Access network . 3
4.5 Proximity network . 4
5 Requirements for information exchange in the user network . 4
5.1 Overview . 4
5.2 Provisioning . 4
5.3 On-demand status acquisition . 4
5.4 Standardized method for information exchange . 4
5.5 Verification of exchanged digital models . 5
5.6 Security . 5
5.7 Synchronization . 5
5.8 Exchange of digital models . 5
6 Requirements for information exchange in the service network .5
7 Requirements for information exchange in access network . 5
7.1 Overview . 5
7.2 Connectivity . 6
7.3 Standardized method for communication . 6
7.4 Synchronization . 6
7.5 Transaction method . 6
7.6 Support of mobility . 6
7.7 Security . 7
8 Requirements for information exchange in proximity network . 7
8.1 Overview . 7
8.2 Support of local connectivity . 7
8.3 Support of adaptation . 7
8.4 Support of data volume, transmission efficiency, and storage . 7
Annex A (informative) Technical discussion — Implementation options for digital
twin framework for manufacturing . 8
Annex B (informative) Dynamic scheduling use case .13
Annex C (informative) Advanced metrology use case .21
Annex D (informative) Optimization of material removal operations use case .29
Annex E (informative) Example of enhanced G-code .39
Bibliography .41
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, 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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
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.
This document was prepared by Technical Committee ISO/TC 184, Industrial 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 the creation of digital twins of observable
manufacturing elements including personnel, equipment, materials, manufacturing processes, facilities,
environment, products, and supporting documents.
A digital twin assists with detecting anomalies in manufacturing processes to achieve functional
objectives such as real-time control, predictive maintenance, in-process adaptation, Big Data analytics,
and machine learning. A digital twin monitors its observable manufacturing element by constantly
updating relevant operational and environmental data. The visibility into process and execution
enabled by a digital twin enhances manufacturing operation and business cooperation.
The type of manufacturing supported by an implementation of 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 and communication protocols.
The scopes of the four 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.
Figure 1 shows how the four parts of the series are related.
v
Figure 1 — ISO 23247 series structure
Annexes A to E provide use cases that demonstrate the digital twin framework for manufacturing.
The use cases are in the discrete manufacturing domain and the digital twins are modelled using the
ISO 10303 series. In other domains, different standards and technologies can be used. For example,
in oil and gas, the digital twins may be modelled using the ISO 15926 series, and for building and
construction, the digital twins may be modelled using the ISO 16739 series.
vi
INTERNATIONAL STANDARD ISO 23247-4:2021(E)
Automation systems and integration — Digital twin
framework for manufacturing —
Part 4:
Information exchange
1 Scope
This document identifies technical requirements for information exchange between entities within the
reference architecture.
The requirements for information exchange in the following networks are within the scope of this
document:
— user network that connects the user entity and the digital twin entity;
— service network that connects sub-entities within the digital twin entity;
— access network that connects the device communication entity to the digital twin entity and to the
user entity;
— proximity network that connects the device communication entity to the observable manufacturing
elements.
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, Automation systems and integration — digital twin framework for manufacturing — Part 1:
Overview and general principles
ISO 23247-2, Automation systems and integration — digital twin framework for manufacturing — Part 2:
Reference architecture
3 Terms and definitions
For the purposes of this document, the terms and definitions given in 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
device communication entity
(set of) system or device providing device communication
EXAMPLE A cell controller sending instructions to the devices in a manufacturing cell, and collecting results
from sensors on the devices.
[SOURCE: ISO 23247-2:2021, 3.4]
3.2
digital twin entity
(set of) system(s) providing functionalities for the digital twins such as realisation, management,
synchronization, and simulation
EXAMPLE A system providing simulation, synchronization, and data analytics for a manufacturing cell.
[SOURCE: ISO 23247-2:2021, 3.6]
3.3
user entity
human users, applications, and systems that use the services provided by the digital twin entity
EXAMPLE An enterprise resource planning (ERP) system that uses the application programming interfaces
(APIs) provided by a digital twin application to update the current status of resources in its database.
[SOURCE: ISO 23247-2:2021, 3.8]
3.4
visualization
use of computer graphics and image processing to present models or
characteristics of processes or objects for supporting human understanding
Note 1 to entry: Example: A visual display of a computerized numerical control (CNC) machine milling an
aluminium block.
[SOURCE: ISO/IEC 2382:2015, modified — Note 1 to entry changed to address manufacturing examples.
Note 2 to entry and Note 3 to entry deleted.]
4 Networking view of the digital twin reference models
4.1 Overview
ISO 23247-2 defines reference models of the digital twin framework for manufacturing, and a functional
view of those reference models. This document defines a networking view. The networking view shall
apply to the reference models given in ISO 23247-2.
Figure 2 shows the four types of communication networks that are used to connect the entities
described in the reference models of ISO 23247-2.
Key
1 user network
2 service network
3 access network
4 proximity network
Figure 2 — Networking view of digital twin reference models
4.2 User network
The user network connects the user entity with the digital twin entity. Through this network, the user
entity makes use of the digital twin instances managed by the digital twin entity.
The user network can be either public Internet or private intranet.
4.3 Service network
The service network connects the operation and management sub-entity, application and service
sub-entity, and resource access and interchange sub-entity. The service network is typically a wired
network running IP-based protocols.
If the digital twin entity is implemented as a single private system, then a service network is not
necessary.
4.4 Access network
The access network connects the device communication entity with the digital twin entity and the user
entity. The data collection sub-entity transmits data collected from the OMEs to the digital twin entity.
The device control sub-entity transmits commands from the user entity or the digital twin entity to
control the OMEs.
The access network can be a wired communication network such as local area network (LAN) or
wireless communication network such as wireless LAN (WLAN) and mobile (cellular) network. The
access network generally adopts IP-based communication protocols regardless of communication type.
4.5 Proximity network
The proximity network connects the device communication entity with the OMEs. Through this
network, the device communication entity transmits commands to OMEs that are industrial devices,
and receives results from OMEs that are industrial sensors.
The proximity network can be an Industrial Ethernet or a proprietary network with a specialized
configuration. Some networks use protocols other than IP. However, if an OME is physically attached or
integrated into the device communication entity then the proximity network is not necessary.
5 Requirements for information exchange in the user network
5.1 Overview
The user network shall enable the exchange of information between the user entity and the digital twin
entity. The information shall be exchanged to enable services and applications such as visualization,
process monitoring, statistical analysis, and simulation. The information is defined in ISO 23247-3.
5.2 Provisioning
The user network shall enable the delivery of information to configure a digital twin to an initial state.
EXAMPLE 1 The digital twin of a product is provisioned at the start of its life from information contained in
Product lifecycle management (PLM). This information can be product requirements, 3D models, configuration,
simulation models, and traceability.
EXAMPLE 2 The digital twin of a work cell is provisioned at the start of its life from information in PLM or
other data sources. This information can be kinematics, capacity, capability, certification, and calibration.
EXAMPLE 3 The digital twin of a process is provisioned at the start of its life from information in PLM or
other data sources. This information can be high-level and low-level process plans, production schedule, and
manufacturing requirements.
5.3 On-demand status acquisition
The user network shall enable the delivery of information on the current state of the OMEs as
represented by its digital twin.
The user network shall enable the delivery of information on the historical state of the OMEs as
represented by its digital twin.
EXAMPLE 1 A user entity queries a digital twin entity, so that it can show the current status of a machine by
creating a visualization of the current geometry of a part.
EXAMPLE 2 A user entity queries a digital twin entity, so that it can dynamically predict the remaining life for
a cutting tool by analysing its previous machining activities.
5.4 Standardized method for information exchange
The user network shall use standardized methods for exchanging information.
NOTE As described in A.2.1, examples for standardized protocol include REST and HTTP.
5.5 Verification of exchanged digital models
The standardized method for information exchange should include methods for verifying the syntax
and semantics of the exchanged model and validating its contents.
NOTE As described in A.2.1, examples of information models with methods for checking syntax and
semantics include STEP and QIF.
5.6 Security
The user network shall maintain security and privacy of the digital twin.
NOTE Standard such as IEC 62443 define a protocol for secure communication.
5.7 Synchronization
The user network shall enable applications to operate on digital models that have been appropriately
synchronized. The rate of synchronization depends on the application.
5.8 Exchange of digital models
The user network shall enable exchange of information about the digital representation of the OMEs.
The communication shall allow applications to operate on common models of the OMEs. Depending
on the application, it is possible that the types of OMEs shown in Figure 3 need to be modelled for
information exchange.
Figure 3 — Type of digital models for exchange
NOTE Several standards define information for one or more of the OME types but no single standard has
been identified for all types of OME at the time of publication.
6 Requirements for information exchange in the service network
The Service network is used to transmit information between sub-entities of the digital twin entity. As
such, this network can be private to a particular implementation of the digital twin entity and does not
need to be defined by this document.
7 Requirements for information exchange in access network
7.1 Overview
The access network connects the device communication entity to other entities. The device
communication entity collects information about the OMEs as they operate using an appropriate
streaming protocol. The device communication entity controls the OMEs by sending commands in a
language understood by the OMEs.
7.2 Connectivity
Depending on the circumstances, a connection to the device communication entity may be discovered
dynamically using an appropriate protocol or using a fixed network address. In either case, the
connection delivers data about the OMEs to the digital twin entity.
EXAMPLE 1 With a fixed network address, an MTConnect agent for a machine tool on the shop floor is
published to the network as URL 192.168.0.1:5000. In this case, the digital twin for the machine tool uses this
address to listen for changes to its OME.
EXAMPLE 2 With a dynamic network address, an MQTT subscriber discovers the availability of a data stream
from the device communication entity responsible for the OMEs and uses the information to update its digital
twin.
7.3 Standardized method for communication
The access network shall provide a standardized method for delivering data collected by the device
communication entity. The method shall include information sufficient to identify the OMEs, and
describe each change that has occurred to a monitored characteristic of the OME.
The access network shall provide a standardized method for delivering data to control the OMEs
through the device communication entity.
7.4 Synchronization
The access network shall enable the digital twin to be connected to its OME. The bandwidth and latency
shall be sufficient to support the required level of synchronization.
NOTE 1 IEC has defined standards that describe various synchronization methods for industrial enterprises.
NOTE 2 The latency requirements for servicing an urgent fault or alarm are different to those for updating a
3D model.
7.5 Transaction method
The access network shall support any of the three types of transaction methods that follow:
— PULL method: requester requests information from the provider;
NOTE 1 The digital twin entity is the requester and the device communication entity is the provider.
— PUSH method: sender sends new or changed information to the receiver;
NOTE 2 The digital twin entity is the receiver and the device communication entity is the sender.
— PUBLISH method: publisher publishes data to be received by the subscribers.
NOTE 3 The digital twin entity is the subscriber and the device communication entity is the publisher.
The PUBLISH method is recommended, when multiple digital twin entities are listening to a single
device communication entity.
7.6 Support of mobility
If the network location of the device communication entity changes, then the access network shall
maintain the connectivity to its digital twin.
7.7 Security
The access network shall maintain security and privacy of the digital twin.
NOTE Standards such as IEC 62443 define protocols for secure communication.
8 Requirements for information exchange in proximity network
8.1 Overview
The proximity network is an interface between the device communication entity and the OMEs. The
proximity network is not necessary if the device communication entity is hosted on the OME.
8.2 Support of local connectivity
The proximity network shall connect the device communication entity to the OMEs using industrial
ethernet or a proprietary network.
8.3 Support of adaptation
The proximity network shall support adaptation of data received from OMEs to data that is understood
by the device communication entity.
8.4 Support of data volume, transmission efficiency, and storage
The proximity network shall support data volume, transmission efficiency, and storage necessary to
transmit information between the device communication entity and OMEs.
Annex A
(informative)
Technical discussion — Implementation options for digital
twin framework for manufacturing
A.1 Acronyms used in Annexes A to E
This clause lists acronyms of protocols or standards that can be considered as an implementation
options of digital twin framework for manufacturing.
3D PDF 3-dimensional portable document format
AAS asset administration shell
AES advanced encryption standard
AMF additive manufacturing file format
API application program interface
ASTM American society for testing and materials
AutomationML automation markup language
B2MML business to manufacturing markup language
CAD computer aided design
CAM computer aided manufacturing
CBC cipher-block chaining
CCM counter with CBC-MAC
CFX connected factory exchange
COLLADA collaborative design activity
EASA European aviation safety agency
ECDHE elliptic-curve diffie–hellman
EtherCAT ethernet for control automation technology
FAA federal aviation administration
FBX filmbox
HTTP hypertext transfer protocol
IoT Internet of Things
IPC inter-process communication
ISA international society of automation
JSON Javascript object notation
JT Jupiter tessellation
LwM2M lightweight machine to machine
MES manufacturing execution system
MOM manufacturing operations management
MQTT message queuing telemetry transport
MTConnect machine tool connect
OCF open connectivity foundation
OPC-UA open platform communications - unified architecture
OpenGL open graphics library
PLC programmable logic controller
PSK phase-shift keying
QIF quality information framework
RAPINet real-time automation protocols for industrial ethernet
RDF resource description framework
REST representational state transfer
RSA Rivest–Shamir–Adleman
SHA secure hash algorithm
STEP STandard for the Exchange of Product model data
STL standard template library
TSN time-sensitive networking
WebGL web graphics library
XML extensible markup language
A.2 Information exchange examples
A.2.1 General
Figure A.1 shows how information may be exchanged within a digital twin framework using currently
available communication protocols.
Key
OME observable manufacturing element
(solid line): within scope of digital twin
(dotted line): out of scope of digital twin
example protocol/implementation
Figure A.1 — Information exchange examples
There are two OMEs configurations in Figure A.1.
— In the first configuration (i.e. left device communication entity/OMEs), data is collected by the device
communication entity through the proximity network and sent to the digital twin entity using the
access network. The OMEs are controlled by the user entity through the legacy communication
channel. For example, a G-Code file is written from a PLM and loaded into the control by an operator.
— In the second configuration (i.e. right device communication entity/OMEs), data is collected directly
by the device communication entity within a single system and sent to the digital twin entity using
the access network. For example, a modern CNC control may support direct numerical control for
data input, and MTConnect for reporting results.
A.2.2 Implementation options for information exchange in the user network
The implementation options for information exchange in the user network are as follows:
— regarding standardized methods for information exchange, the digital twin entity can provide web
services for the user entity using HTTP or REST;
— the digital twin entity can define Open APIs for the user entity. A web interface is one example of an
Open API;
— the digital twin entity and the user entity can use a database or a cloud to share or exchange the
information;
— the digital twin entity can interface with applications such as PLM, MES, and ERP. The digital twin
entity can get manufacturing-related data through interfaces with these applications;
— for applying manufacturing information, the standards that can be used include the IEC 62264
series (i.e. ISA-95) that defines the automated interface between enterprise and control systems.
A B2MML is an XML implementation of IEC 62264. The B2MML can be used to extract information
on manufacturing (e.g., asset tracking, inventory management) that can be applied to the digital
twin. The ISO 16100 series characterizes software-interfacing requirements enabling the
interoperability among manufacturing software tools (modules or systems). The ISO 18828 series
defines information for seamless production planning;
— for supporting visualization, the standard that can be used include ISO 14306 (i.e. JT). The ISO 14306
defines the syntax and semantics of a file format for the 3D visualization and interrogation of
lightweight geometry and product manufacturing information derived from CAD systems;
— CAD/CAM information can be used to create the digital model of the OMEs. The standards that can
be used include ISO 10303-242 (i.e. STEP AP242), ISO 10303-238 (i.e. STEP AP238), ISO 10303-239
(i.e. STEP AP239), and IEC 62714 (i.e. AutomationML). Some applications use a factory layout
(blueprint) to create an initial digital model of the shop floor. The 3D file format can be used to store
information about 3D models. Some popular formats are STL, FBX, and COLLADA. These formats
are used in 3D printing, video games, movies, architecture, academia, medicine, engineering, etc.;
— for embedding 3D models in documents, 3D PDF or 3D rendering can be used. A 3D PDF is a PDF
file containing 3-dimensional geometry. 3D rendering is the process of converting 3-dimensional
models into 2-dimensional images on a computer or document;
— for providing graphical information through the web, WebGL or OpenGL can be used. WebGL is a
JavaScript API for rendering 2D/3D graphics; OpenGL is an API for rendering 2D/3D graphics. In
its modern form, OpenGL is a cross-platform library for interfacing with programmable GPUs for the
purpose of rendering real-time 3d graphics. Its use is common in games, CAD, and data visualization
applications.
— for describing a digital twin model, asset administration shell (AAS) can be used, which is a common
meta-model that is used to describe assets in various format such as JSON, XML, and RDF;
— for supporting verification, the standard that can be used include ISO 23952 (i.e. QIF). ISO 23952 is
an XML based standard that defines, organizes, and associates quality information. A digital twin
can be synchronized with measured values. The accuracy of the predictive results can be increased
through data analytics of the QIF measured values.
A.2.3 Implementation options for information exchange in the access network
The implementation options for information exchange in the access network are as follows:
— regarding standardized method for information exchange, a user entity can access and manipulate
OMEs using protocols such as MTConnect and OPC-UA;
— the user entity can access and manipulate IoT devices (e.g., sensors, actuators) using protocols such
as OPC-UA, OCF, LwM2M, and oneM2M. The IoT protocols have defined various data formats that are
exchanged in the protocols;
— for supporting synchronization, a standardized data format such as ISO/ASTM 52915 (i.e. AMF) can
be used. ISO/ASTM 52915 is an XML-based format for describing objects for additive manufacturing
process such as 3D printing;
— for supporting PUBLISH method, the ISO/IEC 20922 (i.e. MQTT), which defines Client Server publish/
subscribe messaging transport protocol, can be used;
— for supporting near real-time communication, the standards that can be used include the
IEEE 802.1DF, IEC/IEEE 60802. These standards define TSN services for service provider network
and for industrial automation. The TSN is a layer 2 protocol that supports low latency, low delay
variation, and low packet loss;
— regarding security, algorithms that may be used include PSK, ECDHE, CBC, CCM, SHA, and RSA;
— if it is difficult to apply security for services that are overwhelmed with data such as edge computing,
cloud, and IoT data, then the Diffie–Hellman key exchange protocol can be used.
A.2.4 Implementation options for information exchange in the proximity network
The implementation options for information exchange in the proximity network are as follows:
— if the OME already supports protocols such as MTConnect or OPC-UA, then the proximity network
is not needed;
— to support local connectivity, the OME can be connected to the proprietary network or the industrial
ethernet (e.g., EtherCAT, Ethernet/IP, Profinet, Modbus, RAPIENet);
— networked sensors can be used to collect various types of information. For example, the operational
status of equipment may be monitored with a thermal sensor, a vibration sensor, a sound sensor, etc.
Annex B
(informative)
Dynamic scheduling use case
B.1 Overview
Table B.1 describes the example using a template developed by ISO and IEC.
Table B.1 — Summary of the example on dynamic scheduling
ID Case number 1
Use case name Dynamic scheduling of tasks for multiple robots in a manufacturing cell
Application field Smart manufacturing
Life cycle stage(s)/
Production
phase(s) coverage
Status In-operation
Automated manufacturing process adjustment and tracking based on variable condi-
Scope
tions of assembly for a multiple robot manufacturing cell
Manufacturing process requirements can vary based on condition of assembly of
Initial (Problem) incoming components. Manual adjustments of the manufacturing processes are time
Situation consuming and create risk that the appropriate manufacturing process does not
meet requirements or can be improperly tracked.
Objective(s) Automatically adjust processes and maintain production records using digital twins
When large, complex assemblies enter a manufacturing cell, there is a high chance that the in-
coming state of the assembly will not be nominal (missing components, rework requirements.)
Manual adjustments of the manufacturing process are time consuming and increases risk that
the adjusted process is non-compliant or not properly tracked. Digital twins applications can:
Short description
1) determine feature differences between the assembly digital twin and nominal;
(not more than 150
words)
2) adjust manufacturing process requirements based on these feature differences;
3) generate and validate adjusted manufacturing process;
4) monitor the as-manufactured status of the process and assembly.
Manufacturing shop floor personnel, compliance authorities (FAA, EASA, etc.), and
Stakeholders
Robot cell vendors
Key technologies Manufacturing automation for work cells containing multiple robots
AP238 and AP242 to describe digital twins of the process and product
Relevant standards
MTConnect to communicate process and assembly state to build digital twins
ISO 23247 digital twin framework for manufacturing to describe how the standards
Standardization needs
inter-operate on the shop floor
Adoption of the standards by equipment vendors to ensure seamless plug and play
Remaining issues
on the shop floor
and future works
Definition of algorithms/methods for collision avoidance in dynamic environments
B.2 Operational sequences
B.2.1 Process flow
Figure B.1 shows the process flow of the dynamic scheduling of tasks for multiple robots.
Figure B.1 — Process flow of dynamic scheduling
B.2.2 Phase 1: Select
— Step 1: A wing assembly is physically loaded into the robotic manufacturing cell. The supervisory
control is made aware of the assembly type and its instance by use of an Assembly ID.
— Step 2: The supervisory control requests the appropriate Process digital twin (in AP238 format),
wing assembly digital twin (in AP242 format), and process requirements from PLM through MOM.
Once this is complete, the supervisory control knows the condition of assembly (CoA) to be drilled,
and the base process to be executed.
B.2.3 Phase 2: Update process
— Step 1: The supervisory control, using the CoA adjuster, determines which holes do not need to be
drilled, based on the wing assembly digital twin (in AP242 format). It then deactivates the related
drilling working steps in the process digital twin (in AP238 format).
— Step 2: The sequence optimizer then balances and divides the drilling working steps between the
four robots in the manufacturing cell.
— Step 3: The sequence optimizer then optimizes the drilling sequence for each individual robot.
— Step 4: The process digital twin simulates the drilling process and checks for collisions and that all
appropriate holes are drilled.
— Step 5: The updated manufacturing process is sent to the context translator.
B.2.4 Phase 3: Convert and transmit
— Step 1: The context translator extracts relevant context (e.g., workplan, working step, and process
to hole mapping). The context translator then inserts the relevant context into a standardized
implementation of the robots’ native programming language (rapid/enhanced rapid).
— Step 2: The enhanced rapid data is transmitted to the manufacturing cell.
— Step 3: The enhanced rapid data is distributed to the individual robots and the manufacturing
process is begun.
B.2.5 Phase 4: Execution
— The robots report joint motion and significant execution progress (e.g., holes drilled) to the cell
controller using OPC-UA. This data is converted to MTConnect.
— The MTConnect data stream enables the digital twin entity to continuously update the wing
assembly and process digital twins. This information includes robot joint motion as well as working
step completions.
B.2.6 Phase 5: Document
— The updated wing assembly and process digital twins are uploaded back to PLM through MOM.
These digital twins are then used as the CoA for downstream processes and reporting.
— The wing assembly, now containing new holes, is unloaded from the manufacturing cell.
B.3 Mapping to the framework
B.3.1 Overview
Figure B.2 shows how the example may be implemented according to the framework.
Key
Models
product/process
State Stream
plunge complete, etc.
Instructions
G-Codes, etc.
Figure B.2 — Dynamic scheduling of robots
B.3.2 Implementation using framework
Implementation of dynamic scheduling use case with to the framework is in Table B.2 with tags shown
in Figure B.2.
Table B.2 — Implementation of dynamic scheduling use case using framework
ISO 23247 refer- Implementation
Tag Role in use case ISO 23247 name Comment
ence technology
Provides interface to
Windows executa-
PLM through MOM.
Supervisory ISO 23247-2:2021,
A User entity ble using STEP
control 5.3.4
Optimizes process based
modules
on CoA.
Synchronizes process
wing digital twin with
Windows executa-
OME using state stream.
Digital twin ISO 23247-2:2021,
B Wing digital twin ble using STEP
entity 5.3.3
Presents wing digital
modules
twin in AP242 at comple-
tion.
Table B.2 (continued)
ISO 23247 refer- Implementation
Tag Role in use case ISO 23247 name Comment
ence technology
Synchronizes process
digital twin with OME
Windows executa-
using state stream.
Process digital Digital twin ISO 23247-2:2021,
C ble using STEP
twin entity 5.3.3
Presents process digital
modules
twin in AP238 at comple-
tion.
Provisions and retrieves
Models commu- wing and process digital
D User network 4.2 intranet
nications (1) twins when manufactur-
ing is complete.
Sends adjusted manu-
Models commu-
E Access network 4.3 intranet facturing process to cell
nications (2)
controller.
Initial and synchronized
Exchange model Digital twin ISO 23247-3:2021, digital twin representa-
F AP242, AP238
(of OMEs) representations Clause 5 tions for the wing assem-
bly and process.
Caches process state
Data pre- ISO 23247-2:2021, information to assure re-
G Data cache (cell) MTConnect agent
processing FE 6.2.1.2 liable update of wing and
process digital twins.
Converts AP238 into
RAPID using Enhanced
Rapid conventions.
Windows executa-
Context Data translation ISO 23247-2:2021,
In this use case, the
H ble using STEP
translator FE 6.5.3
data translator FE is a
modules
cross-system entity im-
plemented in the device
control sub-entity.
Transfers Enhanced
Instructions Proximity Industrial ether-
I 4.5 RAPID commands from
communications network net
Cell Controller to Robots.
Requirements Process instructions
for information using a standard imple-
J Instructions Clause 8 Enhanced RAPID
exchange
...