Efficient Plant February 2020 - 12

feature | hmi technology
Modern HMIs have matured to
display equipment status and data
such as key process indicators using
increasingly informative and intuitive methods. Courtesy of ADISRA

other intelligent-control-system
elements, along with IIoT field
devices. With an enhanced HMI
application, the data from these
edge devices can be accessed
and evaluated by an HMI application at the edge without the
need to first bring the data back
to a central point.
In fact, an enhanced HMI
can employ various techniques
and standards to move the massaged or raw
data to a cloud-based supervisory database
directly, without the need for SCADA. The
distinction between HMI and SCADA is
thus blurred as modern HMIs can deliver a
full SCADA experience.

MATURE BUT NOT MINIMIZED
Although the modern HMI is a relatively
mature technology in many ways, hardware
and software developments mean that HMIs
are poised to deliver many other capabilities to improve the overall HMI experience
while enabling better human-machine
communication.
Fancy screens and blinking icons have
populated HMI screens for years, providing
real-time understanding of machine and
process dynamics. There was little going on
behind the scenes in a typical HMI application, with any additional requirements
handled by a SCADA system.
But today, HMIs have matured and
adapted to the changing landscape,
becoming more informative and intuitive.
The IIoT and big data have changed the
conversation surrounding HMI. End users
want data in various forms (raw, aggregated,
and pre-processed) to achieve their desired

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goals, including determining analytics
results, key process indicators (KPIs), and
certain enterprise and process metrics.
Achieving these goals provides benefits
for end users and OEMs alike. A 'new and
improved' HMI can be used as a hub or collection point for all data, as well as for data
handling and processing.
HMI evolution has always kept pace with
technology while remaining cognizant of
the need to interface with legacy systems.
This evolution now includes expanded HMI
capabilities for handling data, pre-processing it, communicating it to higher-level
systems, and interfacing with the cloud. One
particular advantage of these new HMIs is
the ability to extract and share data from
disparate systems, for example by using
OPC UA and other industry standards.

DATA-CENTRIC HMIS
Industrial automation data gathering has
typically been performed at a high level in
the control-system architecture, usually
on-premises by a SCADA system. This is
still a good model, but it can be supplemented or even superseded by HMIs configured
to gather real-time field data, store it locally,
and then replicate or forward it to a higher

level on-premises database or cloud-based
system. HMIs can be configured with
sufficient storage to make this possible. This
architecture also adds a level of robustness
to safeguard data in the case of communications problems.
For an HMI to be considered as a datacentric platform, it must be able to handle
data in a persistent manner and not in a
transient fashion. Therefore, data-system
design now becomes a factor in the platform
implementation.

FORWARDING AND
PRE-PROCESSING DATA
Part of the evolution of processes and
machine control is the expansion of available data. Beyond improving performance,
there are many other reasons why specific
data may need to be accessed and processed.
For example, government regulations and
safety requirements can drive what data
needs to be monitored and stored.
Some data points must be allocated as
real-time only, and others may need to be
pre-processed or otherwise filtered for storage. The latter type of data often can use a
slower network to limit required bandwidth
utilization.

FEBRUARY 2020

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Efficient Plant February 2020

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