ANSI/ISA 95.00.03-2005 defines the multi-level functional hierarchy of activities as being comprised of five levels, labeled Level 0 through Level 4. Each level encompasses a time domain (msec, sec, min, hours, shifts, etc.), an activity domain (scheduling, production, monitoring, etc.), and a data domain (inventory levels, production records, sensor values, etc.).

A new paradigm is emerging, one in which the middle man in the data transactions between these various levels is eliminated, thereby eliminating the errors that occur as data pass through intermediate applications, gateways, and protocol conversions. This paper will explore these methods of moving data directly from the source to the final point of use, whether this is an operator console or a data historian archive on disk. In this paradigm, data producers communicate directly with data consumers.

Each of these new methods supports the employment of a new paradigm in process control design, a methodology called Directed Data Transaction Model by the author. This methodology efficiently splits control applications between machine-level control requirements, cell-level control requirements, and enterprise control requirements. Rather than the current approach of making data available to all control elements at all control levels, Directed Data Transaction forms requirements based on data producers and data consumers and structures the design of the control system, including hardware and application software, to meet these specific requirements. This methodology is independent of any vendors hardware or software offering and can be employed on any process.