The deregulation of the electric utility and natural gas industries and, in some localities, the advent of “real-time pricing” for electric power, have introduced a new dynamic into the decision-making processes that determine how these utilities are purchased and managed within an industrial plant. The process becomes even more complicated when an enterprise wishes to manage these utilities at the corporate level for a number of their manufacturing plants. While the optimum energy distributions within each plant can be determined independently, the results are very dependent on the instantaneous prices of the various purchased utilities, each of which may be determined by decisions made at the corporate level and, in some circumstances, can also vary rapidly with time. This has had an impact on the architecture of the local control and data acquisition systems that are located within each plant and has required the addition of interfaces between the plants and the centralized Information Technology systems used at the corporate level.

As a result, the design of modern distributed Control Systems (DCS) is driven by the hardware and software concepts embedded in Information Technology (Yeager (1997)). Control platforms have evolved from the closed systems that used highly proprietary, vendor-specific components, each with their own customized operating systems; towards integrated and open systems that use a variety of standard off-the-shelf hardware and software products. Until recently, standard, commercially available computer technologies simply could not offer the guaranteed response times, multitasking capabilities, redundancy, and industrial reliability necessary for mission-critical control applications. That situation has changed rapidly. Many off-the-shelf, commercially available hardware platforms offer performance capabilities that equal or even surpass the reliability and functionality offered by conventional proprietary distributed control systems and programmable logic controllers (PLC's). In addition, the off-the-shelf operating systems can now provide multi-tasking and real-time features that make them suitable for control applications.

Also, application software developed for business and engineering markets, such as relational database management systems (RDBMS), spreadsheets, and computer-aided design (CAD) programs are finding a home in the control room. This migration of commercial desktop- computing products into the previously closed world of control technology led to the next logical step; applying the emerging Internet/intranet technologies to unify control and business computing systems into one enterprise-wide platform, spanning from the process sensor to the boardroom.