RECONCILING THE TWO TRUTHS OF
EVERY AUTOMATED SYSTEM
By Ian McGregor, Director, Emulate 3D Ltd.
There is something truly awesome about
automated systems which can be easily
overlooked in the everyday work nec-
essary to get them delivered, built, and
commissioned on time. Although their
cathedral-like scale is often impressive in
itself, the feeling of awe is more likely to
come from the fact that these systems are
designed from the ground up to carry
out almost unimaginably complex feats
of organization, reliably and consistently.
There is great satisfaction to be had from
the successful operation of an automated
system, and this success is the result of
a rigorously structured approach to the
system design and performance.
The Two Truths of Automated
Systems
The description of a machine or an
automated system can be approached
in two fundamentally different ways,
each of which results in an equally valid
depiction, or truth. The first of these is
the mechanical description, which starts
as a CAD model. The second truth is the
logical description of how the mechani-
cal system is to operate – and this is the
control system contained within PLCs,
the MCS, and so on. Each of these truths
is developed from an agreed under-
standing of what the system is and how
it needs to operate under various condi-
tions, but they are nonetheless created
from different viewpoints with different
aims.
When Truths Collide
Often the first time the two truths are
brought together is for off-site testing -
once the metal is cut and the CAD has
been transformed into mechanisms,
structures, and devices, and the logical
system is installed in PLCs and higher
8
The Satellite Review
level controllers. An operational auto-
mated system then becomes the result
of three interacting elements, consisting
of the physical system, control system,
and the products that flow through and
trigger it. It is only as the system goes
live for the first time that any dis-
crepancies between the two truths, or
unforeseen consequences of the divid-
ed design approach, become apparent.
Only when all three elements begin to
mesh together can the overall behav-
ior emerge, along with any operational
issues. Whilst the control side of the
system can be relatively easily modified
and reprogrammed, there is a danger
that the easiest solution might result in a
compromise. If there is a better solution
involving changes to the hardware side
of the system, then this would be the
preferred route to take, despite the need
to manufacture new hardware at this late
stage in the project. It is inevitable that
all changes carry a cost and also imply a
delay, neither of which is easily accept-
able in today’s environment of height-
ened expectations. Fortunately, solutions
to this painful situation exist and are
becoming increasingly easy to adopt.
Reconciling the Two Truths
Today’s digital approach provides us
with a better environment where both
parts of the automated system can be
brought together and reliably tested as
an operational whole, complete with the
products necessary to drive the controls.
The virtual commissioning of automat-
ed systems has become possible with
the availability of increasingly powerful
computers and the resulting growth
in 3D CAD models, along with faster
connectivity to real control systems. This
Hardware in the Loop approach requires
the control system to be developed ear-
lier in the project cycle than was previ-
ously necessary in order to enable the
virtual commissioning to proceed which
results in the availability of a robust tool
to produce better automation systems.
The Advantages of a Virtual
Approach are Many and Varied
There are many benefits to carrying
out a larger part of commissioning and
controls testing in a virtual environment,
apart from the obvious advantage of be-
ing able to test the system before cutting
metal. Testing within a virtual environ-
ment takes the logical verification of the
control system off the project’s critical
path, and greatly reduces the amount
of necessary on-site testing. Experience
shows it removes the variable element
of controls testing from the site, making
time estimates and scheduling more ac-
curate. The use of a virtual environment
also allows more exhaustive testing than
may be possible on site. Virtual testing
is considerably safer, easier, and cleaner
to reset following an incident. Comput-
er-based testing can be replicated to car-
ry out several tests in parallel, even if the
use of PLCs limits testing to real time.
The Future is Digital – The
Future is Now
While the two truths of every automated
system and the risks inherent in them
may be unavoidable, the rise in the
availability and performance of dynamic
digital twins in which to test them prom-
ises a more fully verified and robust end
result. Emerging digital test environ-
ments help reduce the risk associated
with investments in automation, as well
as providing a flexible platform for on-
going developments and offline operator
training.
www. WestfaliaUSA.com