Global sales of PLCs will grow at a compounded annual rate of 5.9% over the next four years, rising from nearly $7,000m in 2004 to more than $9,000m by 2009, according to a recent forecast. The study, by the ARC Advisory Group, suggests that globalisation is forcing manufacturers to invest in automation to drive down costs and to raise the quality of their products.

ARC predicts "a modest turnaround in overall capital spending in 2005 and beyond" as manufacturers gear up production to meet rising global demand. "This turnaround should result in a growing demand for automation equipment, including PLCs," it suggests.

ARC also says that incorporation of many elements of information technology into PLCs is making them more attractive as "a centre-stage plant-floor controller" that helps to achieve goals such as improved return on assets and enhanced OEE (overall equipment effectiveness).

• In a separate report, ARC predicts that the global market for DCS (distributed control systems) will grow by about 6% a year over the next few years to reach more than $14,000m by 2009. This expansion will be buoyed by a growth in demand from developing countries such as China and India.