Shades of Digital Twinning
63088, 13 a multinational and multi-
organizational effort to define a reference
architecture model for smart factories, uses
Asset Administration Shell to name digital
models of devices. Plattform Industrie 4.0 is
collaborating with the Industrial Internet
Consortium, where Asset Administration
Shell is seen as a synonym for Digital Twin. current state of the edge and code in the
cloud modeling the states the edge may
take. Having well defined terms for these
various components would help build better
IoT systems. After all, collecting data is just
half the job; ultimately, the behavior of edge
devices will need to evolve as well.
In 2019, the IEEE Standards Association took
the issue to task as well with its “P2806—
System
Architecture
of
Digital
Representation for Physical Objects in
Factory Environments.” 14 The goal is to
define “the system architecture of digital
representation for physical objects in factory
environments. The system architecture
describes
the
objective,
important
components, required data resources and
basic establishing procedure of digital
representation in factory environments.” T HE D EFINITIONS AND F EATURES :
S HELL , P ROXY , T WIN
So what is a twin? The digital twin is not a
proxy for a device, and it is not a command
interface or shell for a device. A twin is a
means of visualizing a device and emulating
what could happen operationally. The
architecture must enable the user to
investigate “what if” questions informed by
actual data from running systems. This is
more than the traditional simulation models
used for product development. Rather,
twinning is a means of refining these models
and extending them from the design and
development phase through deployment
and service phases of the product’s life cycle.
Thus, digital twinning can be extended with
the following definitions:
Some architectures assume the standard
definitions for an Administration Shell are
sufficient. Administration Shell submodels
are being produced relating to functions,
such as safety, or process capabilities, such
as energy efficiency. However, the emerging
and expanding portfolio of subtly
differentiated submodels further add to the
confusion. Each person has a clear picture of
what the different parts are; however, the
industry
needs
standards
and
interoperability, as well as a defined
vocabulary. Administration shells and digital
twins are not quite the same thing and do
not take into account that IoT architecture
requires consideration of code running on
the edge, code in the cloud representing the
13 https://standardsdevelopment.bsigroup.com/projects/2016-03114
14 https://standards.ieee.org/project/2806.html
IIC Journal of Innovation
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Device Shell—a command interface
for code running on a physical asset
on the edge;
Device Proxy—a virtual
representation of the current state
of a device; and
Device Twin—virtual representation
of the device for simulation and
visualization.