"Migration could be the biggest single issue facing automation end-users today," stresses a report from the ARC Advisory Group . ARC estimates that installed automation systems worth about $65 billion are reaching the end of their useful lives. Distributed control systems (DCSs) more than 20 years old will need replacement within the next ten years.
The major driver for migration is the lack of availability of many of the microprocessors used in the original cards; providing the same functionality now requires redesigned cards and often a different hardware base. Many plants will replace their systems with updated ones from the same supplier or retrofits from another manufacturer. For DCS vendors, such work at brownfield sites should account for a vast majority of their business in North America and Europe (Figure 1).
Many stakeholders consider automation a commodity and an unavoidable cost. But, in fact, automation has provided some of the most significant performance improvements at some of the lowest incremental costs. So, chemical makers needing to replace obsolete, unreliable or poorly performing control systems should look beyond just a functional replacement and assess taking fuller advantage of today's technology to achieve increased capabilities and flexibility.
Factors that spur migration projects often include the impact of downtime of existing control platforms, the cost of maintaining obsolete equipment, and the need to acquire or supervise global business data. Compounding the maintenance headache, consolidation among vendors has led to the abandoning of some legacy systems, making their obsolescence cycle even shorter.
The value proposition of the new system includes the economic impact of a combination of not only hardware and software system technologies but also value-added services, such as retention of institutional knowledge, offered by the system supplier in the migration itself. Another key element is minimizing or even eliminating the downtime required to complete the modernization project.
New control systems can unify process variables, business requirements and asset management into an integrated environment that allows chemical makers to transform process control beyond the capabilities of legacy DCS functionality. With the aging of the workforce, today's automation platforms must focus on plant personnel, making the most of their knowledge and codifying it in the control strategies and simulation tools that form part of these systems.
Obsolescence, of course, doesn't happen on a specific date but rather is a gradual process that starts when a vendor discontinues support. Spare parts then become harder to procure and more expensive. At some point, spares become too expensive or too hard to find, obsolescence becomes inevitable and migration must occur.
In general, because the definition of obsolescence is vague, the economics for a system modernization require not upgrading until obsolescence threatens, and not installing soon-to-be-obsolete hardware on new processes. This means that as you add process units and associated input/output (I/O) to your facility it's likely you'll have different generations of control system hardware across your site — further complicating the upgrade decision because some equipment will be end-of-life/obsolete, some "soon-to-be obsolete" and some relatively new. The supplier of your newest I/O probably can provide the tightest integration for it; this can be a significant factor in your migration decision process.