Is legacy producing lag?

When it comes to manufacturing, we all want to increase yield, decrease downtime, improve maintainability, and get more data and information from the plant floor. When trying to achieve these goals, have you come to find out that your legacy control system is impeding your success?

To determine if there is lag in legacy, it’s important to understand what is considered a legacy system these days. After all, the definition of a legacy system itself has changed. In the past, control systems were put in and modified or expanded every few years or once a year at most. In today’s environment, you may be faced with constant change and many new manufacturing requirements. This results in the need for modifications and additions to control systems several times per year.

So what can you do? To meet these changing needs, your existing control system (often installed 10 or more years ago) needs to be more flexible, expandable, and open for connectivity—not typical characteristics of a controller designed a decade ago. But you can revitalize your lagging legacy system in one of three ways: upgrade, replace, or migrate.

To some, upgrading key components, such as a CPU, is a good option, but that type of upgrade can keep you tied to the original manufacturer of your legacy control system. That’s a decision you’ll have to weigh based on technology merits.

Replacement is typically the most expensive option. In today’s environment, this option is a luxury less commonly pursued.

The third method—migration—is often the preferred solution. Typically, though not always, it decreases cost and downtime. Migration leverages existing equipment with new open and modular technologies that can refresh the entire system. But before you head down a migration pathway, consider two key items to ensure success and the results needed to increase yield, reduce downtime, and improve maintainability and connectivity. These items are: 1) tools and programs available from the new control system provider, and 2) the technology of the new control system. Following are critical areas within each item that you should focus on if pursuing a migration.

Tools

• Keep as many existing I/O connections as possible. Reuse reliable parts and reduce costs of rewiring to maximize use existing hardware;

• Use system integrators for experience and domain expertise to maximize options and distribute risks;

• Trade in legacy equipment for credit toward new equipment to maximize previous investments;

• Employ software conversion utilities to migrate useful intellectual property; and

• Use parallel processing capability to keep the legacy system running while the new system is being tested/commissioned.

Technology

• Wide connectivity is needed to meet ever-changing data/information demands for constant business intelligence;

• Openness meets the demands of constant change and provides vendor independence;

• Platform independence helps keep your options open;

• Integrated software environment is needed for improved maintainability, documentation and training; and

• Multi-vendor support ensures openness.

You should also verify all financial justifications for revitalization are directly connected to specific business drivers. Saying “it’s old and we’re risking a shutdown” is not likely to secure funding, even though it may be true. Relate your financial justification and return on investment calculations to business drivers, such as demands for more yield and better quality, ability to feed business intelligence, growing product configurations, and risk management.

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