Legacy Control Problem Solved


With the ending of the first generation of factory automation, there are an increasing number of control systems that are becoming obsolete, presenting a major problem of replacement to the system user. These ‘legacy’ control systems, as they are known, are difficult to maintain and support. Spare parts are a problem, and finding skilled personnel to provide system support, both hardware and software, becomes increasingly difficult.

What all this means for the system user is that the control system that has been running his process reliably for the past several years is increasingly operating upon borrowed time. Moreover, to compound matters, when the system does fail, it will probably be at the worst possible time for production; and getting it to run again will be difficult, and almost certainly time consuming, because, very often, documentation and even the software for legacy systems is lacking.

Now, by working closely with users of legacy systems, Optimal Industrial Automation is able to provide a solution to these problems. By using skills and experience built up over 25-years, Optimal is able to reverse engineer most processes, allowing the replacement of any control system – irrespective of type or make – with a modern equivalent that is well documented and fully supported.

“There are a number of very good reasons for replacing, or implementing the upgrade of a legacy control system before it fails,” said Martin Gadsby, a Director of Optimal. “The first of these is Timing. The change over to a new system can be timed to suit production demands, and so the impact on production is minimised. The second is Cost. An upgrade executed under an emergency situation will cost more, not only in the short term, but also the long term as any payback potential will have been lost. Third, and final, is Functionality Improvements. If the control system upgrade is left until the failure occurs, then there will be a high pressure situation for all involved to get the new system in and running again as quickly as possible. As a result, production improvements will be low on the priority list and will not be implemented.

After the upgrade the system will, therefore, continue to run as it did previously, and any potential improvements that could have given a meaningful payback will have been lost.

The process of upgrading a legacy control system involves Optimal in surveying the system, understanding its functionality and then preparing a detailed functional design specification for a replacement system. Optimal is uniquely qualified to perform these functions, as it has its own complete in-house electrical design and build capability, where full systems can be designed and manufactured. This is complemented by software services that cover the full spectrum, from PLCs through SCADA to DCS, plus high level languages such as C# & VB DotNet, and database work, including real time industrial databases. In addition, Optimal also has the skills to configure and programme machine vision systems, servo systems and robots.

Photo caption: Optimal frequently uses Siemens software and hardware when updating control and information management systems in pharmaceutical plants. Photo acknowledgement: Image courtesy of Siemens AG. Please specify “Siemens press picture” in print.