TABLE OF CONTENTS While discussing the relationship between process model and physical model, we had referred to procedural control, as illustrated in Figure 3.4. Procedural control is the link between process model and physical model. Four levels of recipes and equipment control form a procedural control. Procedural control directs equipment-oriented actions in an ordered sequence to carry out process-oriented tasks.
The procedural model defines the control that enables the equipment in the physical model to perform a process task. Procedural models are used to describe controls that direct the equipment's actions to perform some process-oriented tasks. The procedural model consists of four elements organized in hierarchy, as shown in Figure 4.1.
A procedure is the strategy for accomplishing or carrying out a major processing action. Or in other words, a procedure is a sequence of unit procedures required to make a batch. It is the highest level in the hierarchy of procedural control model, and it orchestrates the control of the equipment in the process cell. As illustrated in Figure 4.2, a procedure can be further sub-divided and defined in terms of unit procedures, and/or operation, and/or phases. The domain of procedure is process cell.
Example of a procedure is making a batch of fiber-cement slurry for making sheets.
A unit procedure is a strategy for accomplishing or carrying out a contiguous process within one unit. In other words,...
