CONTROL & AUTOMATION
SCADA CONTROL SYSTEM
PRODUCTS 4 AUTOMATION
SCADA KEEPS ON EMBRACING NEW TECHNOLOGIES TO
IMPROVE AND EXTEND ITS CAPABILITIES
Ethernet connectivity and HMIs have driven
change through SCADA control systems,
making them radically easier to design,
install and operate, thus lowering the cost of
ownership for operators.
The physical appearance of SCADA
(supervisory control and data acquisition)
control systems has changed notably over
the last 10 years, but then so have control
panels…
Traditionally each control panel whether
for a machine or a control station for an
entire plant was built as a bespoke item and
included a range of dials, gauges, controls
and pushbuttons.
There was usually a unique schematic with
integral indicator lamps that showed the
status of the plant or machinery under
control.
Making custom physical panels is time
consuming and therefore expensive.
Furthermore, they are inflexible, so if
changes are made to the plant or machinery
substantial changes almost always had to be
made to the control panel.
Today all of this can be replaced by one or
more off the shelf graphics display screens
or, as they are more commonly known,
human machine interface (HMI). Often these
are touchscreen operated, although some
operators prefer to have separate controls.
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The display screens can vary from simple LED
read outs, to large format high resolution
flat screens upon which can be displayed a
vast array of schematics, data (real time and/
or historic), warnings and alarms. They can
also be used to call up videos (instructional
or live feeds from cameras around the plant),
instruction manuals and augmented reality
displays.
Their data processing power means they
can turn raw field data into up-to-the-
minute, easily understood, high level plant
and process information so that operators
know the precise status of machinery and
processes.
The screens are often also set up to provide
access to the internet, to interface with other
plant and machines and/or to interface with
IT systems providing enterprise management,
raw materials management and dispatch
logistics. Multiple HMI screens dotted
around the plant provide further easy access,
alongside central control rooms and possibly
even in remote or off-site management
offices.
Usually the various levels of function are
protected by different passwords so that only
authorised personnel can see higher levels of
information and make major changes to plant
settings, while operating personnel still have
access to all appropriate information and
functions.
Ethernet
Simultaneously with the HMI revolution
there has been a shift behind the scenes of
SCADA installations, namely the adoption of
rugged Industrial Ethernet and other single-
cable technologies. Put simply, Ethernet
is a communications solution that has the
potential to massively reduce the wiring
needed within a control system. It can do this
because an Ethernet cable is able to transmit
signals from multiple devices, whereas
conventionally each device required its own
dedicated cable. This can cut installation time,
cost and effort by very significant amounts
and often reduces hardware costs.
Further – and probably more important
in the long run – Ethernet makes system
reconfiguration very much simpler, so that
plant and machinery can be easily altered to
meet changing needs. In fact, it is fair to say
Ethernet often reduces systems re-wiring
from a job of great complexity to one of
plug and play simplicity. This enables and
encourages frequent plant reconfiguration
so that it is constantly reoptimised to meet
changing market requirement. Enabling
emerging technologies like HMIs and
Ethernet are just two aspects of how modern
SCADA has evolved to become simple,
adaptable and very cost effective.
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