By
Paul Goss, ABB
New technology is fast finding its way into modern paper mills and the technology
that controls the paper processes, something that we welcome with open arms
as these technologies help us to visualize and control the papermaking process
better.
For successful lifecycle support it is important to realize that this new
technology comes together with new challenges for maintenance of these systems
throughout their lifecycle. A modern automation system is an evolving structure
that has a continuous life cycle, and with correct maintenance can provide
its users with the highest possible benefit at the lowest risk.
Along with ensuring high reliability, keeping an industrial automation system
up to date will allow the user to easily take advantage of new and advanced
technologies, without having to exchange the complete system.
Around 50 years ago the first attempts where made to introduce microelectronics
into automation technology, starting the era of modern solid-sate controls
in industrial automation. For the first 25 years the market was determined
by the supplier’s standards. The established suppliers developed and manufactured
their systems from scratch, each supplier applying its own system philosophy
and system architecture.
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The second 25 years shows a clear change to a more open
architecture. With the increased need to understand the production processes
better, the data available in the systems had to become more accessible.
Data exchange between systems in horizontal (between multiple controls systems)
and vertical (between control systems and mill management systems) direction
became a necessity.
At the same time as the industry increased the need for process data,
the available technology changed and with that the general philosophy of
the industrial automation system. The personal computer (PC) started to
dominate the scene and opened the world of computers to the general public.
Bill Gates and Paul Allen successfully developed and marketed user friendly
programs that ran on Ed Roberts’ computer assembly kit, the Altair, and
with that the era of Windows was born. |
In the late 1990s the focus of the industry for industrial automation was
towards these PCs and the Windows operating system. The visionaries promoted
a common network backbone allowing all systems independent of supplier to interface
seamlessly. This common system architecture was derived from the office automation,
where such architecture was, and still is, common practice. Although there
are slight deviations from this early vision, the main idea is in place. Intersystem
communications have been standardized on standardized fieldbus and networking
technology. Data storage, handling and visualization have been standardized
on PC and server technology.
The industrial automation system of this day and age consists of three main
product layers, each with its own characteristics:
• Layer 1: I/O and field device layer
• Layer 2: Control layer
• Layer 3:
Operator interface and data management layer
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The interface to the process, the field layer, is based
on hardware and communication compliant with fieldbus standards. The trend
is that this hardware is becoming more and more interchangeable among the
different platforms.
The control layer is the foundation of automation, based on purpose-built
hardware, control and engineering software. In general this layer is driven
by the control application, resulting in the software not to be portable
among the different platforms
The third and most standardized layer is the operations and data management
layer. It’s this layer that brings IT into industrial automation and in
most cases is based on the Microsoft platform, common with business systems,
and custom off-the-shelf (COTS) client, server and network hardware.
Especially in this third layer the use of COTS technology has had a major
effect on system capability and functionality but also brings new challenges
to the way we maintain a modern industrial automation system.
If we take a closer look at the three levels described previous it can
be concluded that each has its own characteristics and with that how we
manage the maintenance of each of these; |
• Layer 1, I/O and field device layer is based on hardware and communications
that in most cases apply established (fieldbus) standards, this enabling easy
interchange among the different platforms. Configuration changes at this level
are accompanied with a medium risk. The typical lifespan of the system components
is 10-15 years.
• Layer 2, control layer consists of purpose built hard and
software, in most cases based on commercially available central processing
units (CPU) and operating systems (OS), in some cases embedded. In the
control layer the custom built application software is housed. Changes
at this layer are therefore of higher risk. The lifespan at this layer
is in general 15-20 years.
• Layer 3, operations and information
management level, is the most standardized throughout the industry from
a hardware and software objective. The use of COTS hard and software at this
layer allows for easy expansion of functionality but also has the shortest
life-span, typically 4-6 years. It is this last layer that brings the most
chllenges to the maintenance and service of a modern industrial automation
system. To be able to ensure a long-term reliable platform several aspects
have to be addressed:
• Increased
complexity of the systems has lead to a change in the level of interaction.
Where in the past the maintenance engineer could repair system parts
at component level, increased complexity, reduced size and applied techniques
such as surface mounted devices (SMD) in many cases allow exchange of parts
only at printed circuit board (PCB) or even at unit level.
• With more and more COTS products being applied, industrial
automation suppliers and users are confronted with new releases, which
can cause compatibility issues.
• Technology is evolving ever faster, with new functionality coming on-line
at an increased pace. To provide optimum benefit, the systems should be
easily upgradeable.
From the above we can conclude that maintaining a modern
automation system is vastly different from what it was when the focus was
mainly on two areas: namely modification and expansion of the application
software; and repair of system components. Maintaining the application is
still a main focus area of a modern system; the repair of system components
however, is being replaced with exchanging at unit level and the need to
keep systems up to date. Maintaining and managing the system lifecycle is
becoming an important focus area for the mill maintenance department. |
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THE FOUR STEPS
A modern automation system is an evolving structure that
has a continuous life cycle, that requires the correct maintenance to
provide its users with the highest possible benefit at the lowest risk and
costs.
Four S’s (steps) can be defined to assure successful life cycle management:
• Set-up
• System integration
• Software management (Sentinel)
• Support
(remote)
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A good life-cycle management program starts when the system
is initially set-up; the system has to provide the mill with the correct
functionality, without compromising the upgradeability of the system at
hand.
In a modern paper mill different system are required to communicate together
(horizontal integration) as well as communication to the mills business
systems (vertical integration). In many traditional mills the required
functionality is covered by a number of (stand-alone) systems. Upgrading
one system can impact the overall picture, with unwanted side effects.
Integrated solutions such as those provided by ABB can be seen as one system,
providing a clear and predictable upgrade path with minimal impact on communication
links.
An important aspect of assuring system reliability is timely upgrades
of the different system layers, especially layer 3, the operations and
data management level, requires increased attention, the COTS hardware
and software used at this layer typically has a life span of 4-6 years.
Managing the impact on production and minimizing the costs of these upgrades,
is something that maintenance managers are often confronted with. The ABB
Sentinel software management program allows the customers to easily evolve
to the latest available software, insuring up-to date systems that are
current with the latest technology and easily expanded with new enhanced
functionality. |
In the case of a system defect the system downtime can be reduced by making
use of the remote support functionality that all ABB IndustrialIT based systems
support. From remote support centres experts can log into the systems determine
the defect and instruct local mill personal what parts to exchange, reducing
the time that is lost, due to travel in a conventional on-site intervention.
The remote support allows for continuous remote monitoring of the system,
so that interventions can be made before failures actually affect the production
process. For customers that provide their own maintenance, the remote support
provides on-line maintenance program assisting users to perform optimal and
timely preventive maintenance.
EVOLVING SYSTEM
With the changing of the industrial automation system architecture it is
important to adapt a new way to maintain industrial automation systems. To
insure the highest benefit at the lowest risk, one must manage the system
life cycle actively, starting with the initial system setup creating the maximum
functionality based on system standards and maximum integration. A good software
management program supporting cost effective system upgrades, combined with
the advantages of remote support will ensure a reliable evolving system providing
the highest benefit at the lowest risk and costs.
