Automation
and information systems represent a major investment for industrial businesses,
both large and small. Long-term protection of that investment should be a
significant consideration when selecting a partner and a system.
Scalability
on all levels is key to the true value and longevity of a SCADA
solution. It is extremely important to be able to evolve solutions over time,
expand them into previously unforeseen areas, and integrate them with other
systems which may or may not already be in place.
Combining a truly scalable implementation
with ease-of-use and outstanding functionality and connectivity will provide
for a sound supervisory software solution and real investment protection for
the future.
This post covers scalability options such as:
Functional Scalability, Solution Scalability, Vertical Scalability, Horizontal
Scalability,“Baked-in” Scalability and suggestions to provide real investment
protection for the future of your industrial operations.
Functional Scalability
Traditional small projects involve low
initial cost, low risk and short implementation time, which are all important
characteristics. However, many small projects are difficult to functionally
extend and very difficult to scale. In contrast, traditional large projects are
more functionally complete and enjoy full-scale implementation, but they have
much higher initial costs, require much longer implementation time and carry
much higher risk. What is needed, is the ability to start with a small
implementation and grow to the size needed, when needed, with modest
incremental effort and without increased risk. Traditionally, the underlying software
platform has been an enormous constraint; small systems simply have not been
designed to grow into large systems without completely replacing the underlying
architecture (see Figure above). A truly scalable software platform, one
explicitly designed with scalability in mind, effectively removes these
constraints and enables a smooth evolution of the software solution from small
to as large as the business requires, without replacing the underlying
technology. A proven way to solve this scalability issue is to build the system
around a plant model, which supports the gradual evolution of an application by
permitting additional attributes and functionality to be added to the solution
and deployed throughout the operation from any given development station
Solution Scalability
Growing a system from small to large requires
another dimension of scalability in addition to functionality. True scalability
demands that a solution can be easily extended from a single, simple
application, perhaps a single machine, to a comprehensive networked solution
serving the needs of an entire multi-plant industrial enterprise. Consider the
common requirement to have multiple HMI or SCADA applications that are
different but have similar components, which must be kept separate but benefit
from each other’s design and standards. Also, consider the requirement for
those applications must be able to operate, evolve and grow independently. This
is a typical real-world scenario which requires an underlying system
architecture to support such evolution. Such an architecture needs to combine
powerful object-oriented modeling capabilities, integrated and equally powerful
graphical HMI and visualization capabilities as well as comprehensive device
integration capabilities. As someone responsible for such a system, you would
want maximum re-use of engineering effort where appropriate, with flexibility
where required; common application logic with device-independence; consistent
application visualization with standardization, security and application-specific
detail; all of which can be deployed and managed from a centralized,
standards-based environment.
Vertical Scalability
An HMI or SCADA supervisory system is just
one part of an industrial operation, albeit a significant one. In the same way
that each department in an organization needs to integrate and collaborate
smoothly, supervisory systems need to integrate and enable collaboration with
other systems in an industrial enterprise. Effective industrial software
solutions must be capable of efficient, scalable integration with
enterprise-level systems such as ERP, Supply Chain Automation, Enterprise Asset
Management and other corporate systems for planning and reconciliation. To
satisfy this important vertical integration need requires purposeful
architectural design, and great support for standards such as XML, OPC® and
SQL complemented with Web Services and ISA-95/XML B2MML support (see Figure below).
Figure 2. Overview of a Scalable Connectivity and Software Integration Architecture
Vertical
scalability also means scaling to the plethora of field device connectivity
requirements that exist today. While some SCADA and HMI supervisory systems may
provide direct interfaces to physical devices such as RTUs and PLCs, these
interfaces are typically simplistic and foster integration solutions which are
too closely tied to the physical hardware; that simplistic builds limitations
and constraints into the implementation. To achieve true scalability for device
connectivity, a software architecture that provides a level of abstraction from
the specific devices is required. What does this mean in practice? Well, it
means for example, that a device independent application could be developed for
a project using one specific family of PLCs, and making use of all of the
connectivity capabilities provided by that device. This first step matches the
benefits of the direct approach. However, real benefit becomes apparent when it
becomes necessary to automate a similar area at a facility — one that was built
at a different time and uses a completely different family of PLCs and
automation equipment. With a robust and well-designed device integration
architecture and software, the application can be easily re-purposed for a
different family of hardware devices without incurring the engineering expense
of changing the application. Multiply that efficiency over many pieces of
equipment and many different hardware systems, and the result is a truly
scalable software solution. Of course, implementing the application is just
part of the effort. For effective scalability, it is necessary to be able to
configure, monitor and run diagnostics on multiple I/O interfaces from a
convenient central location. Consequently, such an architecture requires
comprehensive remote management capabilities, built-in diagnostics and the
flexibility to deploy in a variety of architectural topologies to suit the needs
of the industrial enterprise — the hallmarks of a truly scalable
infrastructure.
A truly
scalable approach separates application code from device communications
management, so both can be easily managed and updated:
Takes a flat communications model and adds
structure and better manageability
Makes individual communication paths
available globally for any application to use
Enables
communications and device naming to be different for the same application,
facilitating re-use on any machine
Horizontal Scalability
Supervisory, HMI and SCADA systems do not
operate in isolation. They need to integrate smoothly and reliably with a wide
range of peer-level systems including MES, DCS, Historians, LIMS, Workflow,
Field Mobility Solutions and Quality Management systems. Historically, the
solution to these kinds of integration challenges has consisted of crude
interfaces using proprietary interfaces, middleware and limited data-level
integration. These approaches, while barely satisfactory for standalone
solutions, are the antithesis of scalability, and require custom engineering
approaches and significant expenditure for system integration work. A truly
scalable solution for horizontal integration of this kind requires an
architecture designed with scalability and integration capabilities built-in
(see Figure 2). Embracing standards such as OPC, SQL, OLE DB/ADO and XML with
an object-oriented architecture delivers the most easily scalable industrial
software solution set available.
“Baked-in” Scalability
Traditionally, scalability cannot be added
into operational systems after the fact. True scalability comes from purposeful
design. Legacy systems can be integrated into a scalable infrastructure, but
the real benefits come from starting with the right software platform. A truly
scalable platform must be developed from the ground up to provide ease-of-use
on day one, and scalability for the lifetime of the operation. This “baked-in”
scalability comes from a powerful, pragmatic, object-based engineering
environment that enables valuable engineering and best practices to be re-used
and securely deployed across multiple facilities, without physically visiting
each facility. This scalability also comes in the form of centralized
management, which permits oversight, configuration, diagnostic analysis, and
security management of entire automation systems deployed across numerous
computers that are geographically distributed across a multi-site industrial
enterprise. Training, skills and familiarity with automation systems in one
area of operation are immediately transferable to different areas. This kind of
scalability delivers tremendous economies of scale as automation solutions are
rolled out to new areas of the operation. A unique, logical abstraction of
details, through a model view versus a deployment view (see Figure 3) provides
unsurpassed capabilities to retain and re-use engineering efforts put into a
system, while increasing application functionality, one step
at a time.
Figure 3: Model View and Deployment View
Summary
Functionality,
ease-of-use and scalability are the most important characteristics of any HMI
or SCADA solution. It is these characteristics, which provide real
investment protection for the future.
Wonderware
software’s scalable design and easy-to-use tools uniquely embody these
characteristics — specifically, the powerful Wonderware System Platform and
InTouch visualization tools. With the broadest range of integration options,
powerful MES, workflow and mobile solutions, Wonderware has set a new benchmark
for combining the deepest functionality with ease-of-use unparalleled True
Scalability.
To learn more about Wonderware’s Supervisory
HMI & SCADA Software Solutions visit our website: wondeware.com
Special thanks for the contributions to this
post to Phil Couling, Product Marketing
Director, Supervisory HMI
& SCADA, author of the “ Raising the Bar on Scalability”.
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