TABLE OF CONTENTS As discussed in Chapter 4, a procedure is a strategy for carrying out a process to manufacture a product. For mapping procedural elements and equipment there are many alternatives. In a process cell, there may be units, equipment modules and control modules. An equipment phase may exist within a unit or within an equipment module, and may act on equipment or control modules. There are two types of procedural elements recipe and equipment. Each of the hierarchical levels, procedure, unit procedure, operation and phase, can be either a recipe procedural element or an equipment procedural element. A recipe procedural element is independent of the equipment on which it executes, but an equipment procedural element is specific to a piece of equipment.
In batch management software for recipe execution, all the procedural elements in the batch engine are recipe procedural elements. All the procedural elements in the control system are equipment procedural elements. The recipe procedural elements must be linked with equipment procedural elements. The ISA S88 standard allows procedural elements to be linked across any level. Most of the batch management software systems link recipe procedural elements and equipment procedural elements at the phase level, as illustrated in Figure 4.6. In such cases, the equipment phase is the only procedural element that is specific to the equipment. The equipment phases typically run in the PLC/DCS systems. The recipe phase is run in batch engine.
Each equipment procedural...
