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Many companies with automated system that were installed in the 1980's and early
1990's face the problem of ageing equipment and systems that can become
unreliable and difficult to maintain, support and upgrade.
Ageing equipment and outdated systems bring the dilemmas of "whether to
upgrade", "what to upgrade" and "how to upgrade". Retrofitting an existing
system is a daunting task, with a wide range of suppliers and an ever
increasing range of technology to consider.
As automation systems are such a major asset and critical to day-to-day business
activities, companies must tread very carefully to avoid making costly
mistakes. One pitfall to be aware of with "one-shop suppliers", is that they
may recommend the replacement of 'the entire automation system', since this is
far easier and far more profitable than integrating with your old, existing
equipment.
Complete retrofits of the entire automation system are often not necessary;
often only parts of the system are actually outdated and require attention.
These parts can usually be brought up-to-date without any effect or impact on
the rest of the automation system.
On older systems multiple components may require replacing, and here a phased
replacement approach is often best. In a phased approach different components
of the system are upgraded or modernised over a number of years, this makes it
easier on the company, spreads the financial outlay and greatly minimises the
impact of the retrofit.
A carefully staged approach will help ensure the right decisions are made and
the right parts of the system are upgraded.
Automation systems consist of a tangle of integrated equipment, devices and
systems, so companies should first try to break down the component parts of the
system and review each one in turn, questioning its reliability,
maintainability, supportability and upgradeability. Once this has been done for
all component parts a clear picture should start to appear about which elements
of the system require attention, these can then be suitably ranked in order of
urgency, from those that require urgent attention to those that are up-to-date.
When analysing each component it is worth establishing key objectives that any
retrofit should address, these should include the infrastructure associated
with the component, for example old cabling and associated hardware that needs
eliminating, renewing or replacing with newer technology. Companies should then
review the solutions and technology available to replace each component and
decide what is best for their business, keeping open-minded and focusing on
what is best suited to the objectives and the "business operation" rather than
focusing on "what works with our current system".
The compatibility issues of combining old and new equipment is obviously a very
important one, however solutions do exist, like our Serial and
Network Protocol Conversion Software called Gipsy, which allow the
seamless integration of new technology equipment with old systems and vica
versa . In some cases you will not get the full benefit of the new technology
until other parts of the system are upgraded too, but you'll be a step closer
to utilising such new technology.
Despite what people may say, integrating old and new equipment and technology is
often possible and in some cases relatively straightforward. The key is to
successfully determine and fully understand the 'interface protocol' for your
automation equipment. Protocols of new equipment should be easy to identify and
be well documented, however details of old equipment may be difficult to find.
As a last resort a 'protocol analyser' can be utilised to help unravel the
protocol mystery of old equipment. Once you have all the relevant information,
the actual data of each protocol must be compared and matched up. Providing
this protocol data has some degree of compatibility a 'protocol converter' can
be implemented to translate between old and new protocols.
A protocol converter can be introduced as a permanent or temporary solution. In
fact protocol converters play a vital role in a phased retrofit project, since
they enable integrated systems and equipment to be 'de-coupled' allowing
individual components of the system to be upgraded or replaced.
Any introduced protocol converter will be a critical part of an automation
system, it must be robust and reliable or the system will fail. Many retrofit
projects have run into major problems and delays simply due to unreliable or
incorrect protocol conversion. So ensure the protocols are fully understood and
the protocol converters are fully tested before they are introduced into the
live system.
A major area, often overlooked until it's too late to change the retrofit
strategy, is that of how to actually implement the retrofit with minimum impact
on the businesses operations. Automation systems often operate 24*7 so planning
suitable periods for installing, commissioning and go-live of retrofitted
systems and/or equipment is often extremely difficult. Hence an implementation
plan should be drafted very early on in the project. Often phased retrofits are
the only way to upgrade a system without major disruption to the businesses
normal operations.
Periods of "low activity" should be identified early on in the project; these
may be weekends, weeks in the year, hours of the day, bank holidays, etc. These
are key periods that should be earmarked for the retrofit well in advance.
Where necessary production shifts, deliveries, etc. may need to be rescheduled
or revised to create suitable periods for the retrofit to take place.
The time required and the impact of the retrofit varies greatly from system to
system, depending on what is being upgraded or replaced. The key is often to
phase the retrofit into smaller chunks, whilst maintaining operation of the
automation system. For example retrofits of automated stacker cranes in a
warehouse should be retrofitted one by one, returning each one to full
operation before commencing on the next.
For retrofits of conveyors, PLC's or computer systems, it is usually impossible
to get a single time window to accommodate the whole retrofit so a switch-over
plan must be devised early in the project. This plan should detail how the
system can be switched between the old and the new and vice versa. In some
cases this can be as straightforward as changing some cables, other times it
can be quite lengthy, exporting and importing large databases. This switch-over
capability should remain in place for a few months after go-live in case
problems develop with the new system and the old system needs to be temporarily
reinstated.
With careful planning and adopting the correct strategy, retrofits can be
undertaken seamlessly with minimal disruption to the company's business
operation, employing modern technology and equipment to take the business
forward.
Craig Colclough is a director of Lifetime Software Ltd and, as an expert on
protocol conversion, has assisted many end-users and third-party suppliers on
retrofit projects of large automation systems. For more information or advice
he can be contacted on 01252 687136.
Serial and Network Protocol Conversion Software - Our
protocol converter software.
PLC to PC Interface Software (Allen Bradley PLC's etc.)
- Our software for PLC interfacing and PLC upgrades.
Automated Stacker Crane Interfacing Software -
Our Software specifically for automated stacker crane upgrades.
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